GSTR-1 vs GSTR-3B: The Monthly Tie-Out Guide for CFOs

Key Takeaways

• GSTR-1 Versus GSTR-3B, Defined: GSTR-1 captures invoice-wise outward supply details under CGST Rule 59 and is due by the 11th of the following month for monthly filers. GSTR-3B is a summary self-declaration of tax liability and ITC under CGST Rule 61, due by the 20th. One is the ledger, the other is the cheque. Outward tax declared in GSTR-1 must equal tax paid in GSTR-3B Table 3.1(a), any gap is a liability mismatch.
• The Most Expensive Misconception: Many finance teams assume GSTR-3B can be filed independently of GSTR-1 figures. It cannot, not safely. Under Rule 88C, if GSTR-1 outward tax liability exceeds GSTR-3B paid liability by ₹1 lakh or more, the portal generates a DRC-01B intimation. You then have seven days to pay the difference via DRC-03 or submit an explanation, else recovery under Section 79 follows.
• Interest Exposure Is Automatic And Backdated: Section 50 of the CGST Act charges interest at 18% per annum on unpaid outward tax. Interest accrues from the day immediately after the GSTR-3B due date until actual payment. On a ₹10 lakh shortfall for six months, that is ₹90,000 in interest alone, before any penalty.
• The Amendment Window Is Hard-Capped: Corrections to GSTR-1 and GSTR-3B cannot be made after 30 November of the following financial year or the date of filing the annual return under GSTR-9, whichever is earlier. Miss that window and the only path is a voluntary DRC-03 payment, with accumulated interest.
• A Monthly Three-Step Control Works: Pull GSTR-1 summary by rate bucket, compare to GSTR-3B Table 3.1 figures, resolve every line variance before filing GSTR-3B. Running this in the first week prevents notices, protects ITC for recipients, and creates the workpaper trail needed for GST audits.

GSTR-1 Vs GSTR-3B: The Difference, Explained

GSTR-1 is a detailed outward supply statement, GSTR-3B is the summary return where actual GST liability is paid. They serve different functions but must produce the same outward tax number every period.

The one rule that resolves most confusion: GSTR-1 is what you told the world you sold, GSTR-3B is what you actually paid the government for it. Any difference between the two is a reconciling item, and the department now sees it in real time.

For QRMP filers, the 22nd / 24th split for GSTR-3B follows state groupings published by GSTN: Group 1 states are due by the 22nd, Group 2 states are due by the 24th.

What Is The Practical Difference Between GSTR-1 And GSTR-3B?

GSTR-1 and GSTR-3B are two separate GST returns with distinct functions, one reports supply details, the other discharges tax, but their outward tax figures must reconcile to prevent DRC-01B intimations under CGST Rule 88C.

GSTR-1: The Detail Layer

GSTR-1 captures every outward supply transaction in separate tables. B2B supplies go in Table 4. Inter-state B2C transactions above ₹2.5 lakh go in Table 5. All other B2C supplies go in Table 7. Exports with IGST payment go in Table 6A; exports under LUT/Bond without payment also go in Table 6A with a separate flag. SEZ supplies with payment go in Table 6B; without payment, also Table 6B with a flag. Credit notes and debit notes land in Table 9B.

GSTR-1 does not involve any payment. It is a pure data declaration.

GSTR-3B: The Payment Layer

GSTR-3B aggregates those transactions into five outward supply buckets in Table 3.1:

• 3.1(a): All outward taxable supplies (B2B + B2C, both large and small)
• 3.1(b): Zero-rated supplies (exports with or without IGST payment, SEZ supplies)
• 3.1(c): Nil-rated and exempt supplies
• 3.1(d): Inward supplies attracting reverse charge (RCM), this is where the recipient pays, not the supplier
• 3.1(e): Non-GST outward supplies

The supplier's RCM outward supplies appear in GSTR-1 Table 4B but do not create an outward tax liability for the supplier in GSTR-3B. The recipient accounts for the tax in their 3.1(d).

How The System-Computed GSTR-3B Helps

GSTN now provides an auto-drafted GSTR-3B on the portal, pre-populated from your filed GSTR-1 and your GSTR-2B. This is not the final return, you still need to review and file it, but it gives you a starting point that is already aligned with GSTR-1 figures. Any variance between your own books and this auto-draft is your first reconciling signal.

Frequently Asked Questions About The GSTR-1 And GSTR-3B Difference

What happens if I file GSTR-3B with a lower tax figure than GSTR-1?
If GSTR-1 outward tax exceeds GSTR-3B paid tax by ₹1 lakh or more, Rule 88C triggers a DRC-01B intimation from the portal. You have seven days to pay the differential via DRC-03 or submit an explanation. If neither is done satisfactorily, the department initiates recovery under Section 79 of the CGST Act, plus 18% interest under Section 50.

Can I file GSTR-3B before GSTR-1?
No. For monthly filers, GSTR-1 is due by the 11th and GSTR-3B by the 20th of the following month. The sequence is intentional. GSTR-1 data feeds into the auto-drafted GSTR-3B and into the recipient's GSTR-2B for ITC. Filing GSTR-3B first without matching GSTR-1 increases mismatch risk.

Why Do GSTR-1 Vs GSTR-3B Mismatches Trigger Notices — And What Is The Rupee Cost?

The department's mismatch engine under Rule 88C compares GSTR-1 declared liability against GSTR-3B paid liability for each tax period and issues DRC-01B intimations automatically when the gap crosses prescribed thresholds.

How Rule 88C Works

The portal computes the difference between outward tax declared in GSTR-1 and outward tax paid in GSTR-3B for the same period. If this difference exceeds ₹1 lakh, or a specified percentage threshold, a DRC-01B intimation is generated. The taxpayer receives it on the portal and has seven days to respond. The two options are:

1. Pay the shortfall in full, along with applicable interest, via Form DRC-03.
2. Submit a written explanation for the difference through the portal.

If the explanation is not accepted or no response is given within seven days, the department can recover the amount under Section 79 of the CGST Act, which includes attaching bank accounts or other assets.

The Interest Arithmetic

Section 50 of the CGST Act levies interest at 18% per annum on unpaid outward tax. Interest runs from the day after the GSTR-3B due date until the actual date of payment.

Example: GSTR-3B for April was due by 20 May. You short-paid ₹5 lakh. You pay it on 20 November, six months later. Interest: ₹5,00,000 × 18% × (6/12) = ₹45,000. That is a direct cash loss, not a recoverable credit.

If tax was collected but not remitted, the rate rises to 24% per annum under the same section.

Late Fee Exposure

A delayed GSTR-1 attracts a late fee of ₹50 per day (₹25 CGST + ₹25 SGST). For nil returns, this drops to ₹20 per day (₹10 + ₹10). GSTR-3B carries the same slab: ₹50 per day for returns with liability, ₹20 per day for nil returns. Maximum caps apply based on aggregate turnover and are specified in CBIC notifications. Late fees are not waivable after the fact, they must be paid before the portal allows filing.

Frequently Asked Questions About GSTR-1 Vs GSTR-3B Mismatch Risks

What is the threshold that triggers a DRC-01B intimation?
A DRC-01B is generated when GSTR-1 tax liability exceeds GSTR-3B paid tax liability by ₹1 lakh or more for a tax period. The comparison runs automatically on the portal after both returns are filed. The taxpayer has seven days from the date of intimation to pay via DRC-03 or submit an explanation.

Does filing a revised GSTR-3B stop the DRC-01B process?
GSTR-3B cannot be revised once filed. The only correction path is either to include adjustments in a subsequent month's GSTR-3B, within the amendment window, or to pay the differential through DRC-03. A DRC-03 payment, accompanied by a portal response to the DRC-01B, is the cleanest way to close the intimation and stop further recovery action.

A 30-Minute Monthly Tie-Out: How To Reconcile GSTR-1 Vs GSTR-3B

The gstr1 vs gstr3b reconciliation is a fixed monthly control, not a year-end exercise. Running it before GSTR-3B filing eliminates notices and creates an audit trail.

Step 1: Pull The GSTR-1 Summary By Rate Bucket (5 Minutes)

Download the GSTR-1 summary from the portal after filing. Sort outward supply values and tax amounts by GST rate (5%, 12%, 18%, 28%) and by category: taxable, zero-rated, nil/exempt. This gives you the GSTR-1 tax figure, rate-wise.

Map GSTR-1 Tables To GSTR-3B Sections (10 Minutes)

Use this mapping every month:

Once mapped, the sum of GSTR-1 taxable value and tax by bucket should equal GSTR-3B 3.1(a), 3.1(b), and 3.1(c) exactly.

Step 3: Compare And Identify Variances (10 Minutes)

Build a six-column sheet: GSTR-1 taxable value, GSTR-1 tax, GSTR-3B value, GSTR-3B tax, Value gap, Tax gap. Any non-zero entry in the gap columns needs a reason before you file GSTR-3B.

Acceptable reasons: timing differences, RCM supply value included in GSTR-1 but no outward tax in 3B (correct treatment), or exports reported in GSTR-1 but zero-rated in 3B (correct treatment). Document each reason.

With AiA's Tally Prime sync, outward supply transactions are auto-classified to GSTR-3B buckets as they are posted in Tally. The GSTR-1 vs GSTR-3B delta report runs daily, not just at month end, so variances surface before filing, not after a DRC-01B arrives.

Step 4: Confirm Amendment Window Before Correcting Prior Periods (5 Minutes)

If the variance is from a prior month, check whether you are within the amendment window. Under Sections 37 and 39 of the CGST Act, amendments are permitted up to 30 November of the following financial year or the date of filing GSTR-9, whichever is earlier (CBIC Circular 237/2024). If you are within the window, amend the relevant GSTR-1 table and carry the correction into the current GSTR-3B. If the window has closed, use DRC-03 for voluntary payment.

Frequently Asked Questions About The GSTR-1 Vs GSTR-3B Reconciliation Process

Can I use the GSTN system-computed GSTR-3B as my filing?
The auto-drafted GSTR-3B on the portal is a starting reference, not a final return. It is pre-populated from your filed GSTR-1 and your GSTR-2B. You must review every figure, add any items your books show that GSTR-1 missed, and adjust ITC if GSTR-2B does not match your purchase register. File the reviewed version, not the raw auto-draft.

What documentation should I keep for the GSTR-1 vs GSTR-3B reconciliation workpaper?
Keep the monthly comparison sheet (GSTR-1 summary vs GSTR-3B table 3.1), an explanation note for every variance above ₹50,000, the filed GSTR-1 JSON or summary PDF, and any DRC-03 payment challans. GST auditors under Section 65 of the CGST Act routinely ask for these workpapers covering up to five years of returns.

Fix The Top 7 Mismatch Scenarios — One Rule, One Example Each

Each scenario below covers the gstr1 and gstr3b difference in one specific transaction type, where to report it, and how to correct it. This is where the gstr3b vs gstr1 gap materialises in practice.

Scenario 1: Credit Notes Issued In A Different Month

Rule: A credit note issued in October for a September invoice reduces GSTR-1 Table 9B in October. The tax reduction flows into GSTR-3B 3.1(a) in October, not September. This is a timing difference, not an error.

Example: Invoice of ₹10 lakh (GST ₹1.8 lakh) raised in September. Credit note of ₹2 lakh (GST ₹36,000) issued in October. September GSTR-1 shows ₹1.8 lakh outward tax; September GSTR-3B should also show ₹1.8 lakh. October GSTR-1 shows a credit note reducing tax by ₹36,000; October GSTR-3B 3.1(a) shows the net.

Document the timing difference in your reconciliation workpaper so the September gap does not trigger a DRC-01B response.

AiA posts the credit note JV back to Tally with the correct GSTR-1 table tag (9B) and GSTR-3B bucket assignment in the same transaction. The amendment window tracker flags if a credit note is being posted to a period that has already crossed the 30 November cut-off.

Scenario 2: B2C Large Vs B2C Small Misclassification

Rule: Inter-state supplies to unregistered persons with invoice value above ₹2.5 lakh are B2C Large (GSTR-1 Table 5, invoice-wise). All other unregistered supplies, intra-state at any value, or inter-state at or below ₹2.5 lakh, are B2C Small (Table 7, consolidated) (GST portal Help).

Example: You raise an inter-state invoice for ₹3 lakh to an unregistered buyer. You enter it in Table 7 (B2C Small) instead of Table 5 (B2C Large). The tax figure in GSTR-3B 3.1(a) remains correct, but GSTR-1 has the wrong table. Amend the GSTR-1 in the next month's filing by moving the entry from Table 7 to Table 5 and issuing a correction.

The B2C classification error does not create an outward tax gap but does affect the mismatch checks run by the department on invoice-level data.

Scenario 3: RCM Outward Supplies Included In GSTR-1 But Zero Tax In GSTR-3B

Rule: When you supply goods or services on which the recipient pays tax under reverse charge (RCM), you report the value in GSTR-1 Table 4B. You do not pay outward tax in GSTR-3B, the recipient accounts for it in their GSTR-3B Table 3.1(d).

Example: You provide legal services (RCM category) worth ₹5 lakh to a corporate client. GSTR-1 Table 4B shows ₹5 lakh. Your GSTR-3B 3.1(a) shows this value but no outward tax against it. The gap is intentional and correct. Your reconciliation workpaper should flag it as “RCM outward — tax borne by recipient.”

Scenario 4: Advances Received For Services Not Reported

Rule: Advances received for services are taxable at the time of receipt under Section 12(2) of the CGST Act. Report them in GSTR-1 Table 11A and include the tax in GSTR-3B 3.1(a). When the invoice is raised, reverse the advance in Table 11B. Advances for goods are not taxable, Notification 66/2017-Central Tax dated 15 November 2017 exempted registered persons from paying GST on advance receipts for goods.

Example: You receive a ₹5 lakh advance for a consulting project in April. Declare ₹5 lakh in GSTR-1 Table 11A for April and pay ₹90,000 GST (18%) in GSTR-3B. In May, when the invoice is raised, reverse the advance in Table 11B and net off the tax. Missing the April advance creates a direct GSTR-3B underpayment of ₹90,000 and starts the 18% interest clock.

Scenario 5: Exports And SEZ Supplies With Or Without Payment

Rule: Exports with IGST payment go in GSTR-1 Table 6A and GSTR-3B 3.1(b), IGST paid is refundable from Customs. Exports under LUT/Bond (without IGST payment) also go in GSTR-1 Table 6A and GSTR-3B 3.1(b), but no tax is discharged. SEZ supplies follow the same logic in GSTR-1 Table 6B. A common error is reporting zero-rated exports in 3.1(a) instead of 3.1(b), which inflates taxable supply figures and distorts refund calculations.

Scenario 6: E-Invoice Cancelled After 24 Hours

Rule: An e-invoice can be cancelled on the IRP only within 24 hours of generation. After that window, the e-invoice auto-populates into GSTR-1 and cannot be removed from the portal. If the underlying transaction is reversed, issue a credit note in GSTR-1 Table 9B (GSTN FAQ on e-invoicing).

Example: You generate an e-invoice on 5 June for ₹8 lakh but cancel the deal on 7 June. The 24-hour window has passed. The invoice is already in your GSTR-1 auto-population. Issue a credit note for ₹8 lakh in GSTR-1 Table 9B in June and reduce 3.1(a) accordingly. Not doing so creates a ₹1.44 lakh tax gap (assuming 18% GST) between GSTR-1 and GSTR-3B.

Scenario 7: When To Use DRC-03 Vs Amending Next GSTR-1

Rule: Use the amendment route (correcting in the next month's GSTR-1 and adjusting the current GSTR-3B) if the error is discovered before the 30 November cut-off and the amount is reportable as a current-period adjustment. Use DRC-03 voluntary payment if the amendment window has closed, if you need to close a DRC-01B intimation immediately, or if the amount is material and you want to stop interest from running further.

DRC-03 is a self-admission of liability. It closes the intimation cleanly and avoids Section 79 recovery action.

Frequently Asked Questions About Specific GSTR-1 Vs GSTR-3B Mismatch Scenarios

Do advances for goods need to be shown in GSTR-1?
No. Notification 66/2017-Central Tax dated 15 November 2017 exempted registered persons from paying GST on advances received for the supply of goods. Advances for goods are not reportable in GSTR-1 Table 11A and no tax is payable in GSTR-3B at the time of receipt. Tax is payable only when the invoice is issued at the time of supply.

If I report an export in GSTR-3B 3.1(a) instead of 3.1(b), what goes wrong?
The export value inflates your domestic taxable supply figures in 3.1(a). The IGST paid on exports, if applicable, may not be correctly linked to the refund claim filed through Customs or the GST portal. The recipient's GSTR-2B will also carry incorrect supply classification. Correct this by amending GSTR-1 to ensure Table 6A is populated, and adjusting GSTR-3B in the next period to move the value from 3.1(a) to 3.1(b).

Lock Your Month-End SOP — And What To Automate

A documented monthly SOP converts the gstr1 vs gstr3b reconciliation from a firefighting exercise into a 30-minute control. This is the difference between a defensible audit trail and a reactive response to a DRC-01B.

The Five-Point Month-End SOP

Day 1–8: Close the sales register in Tally. Tag every transaction with the correct GSTR-1 table (B2B, B2CS, B2CL, export, SEZ, RCM outward, advance). Verify e-invoice IRN status, cancel any invalid e-invoices within 24 hours of generation. Post credit notes and debit notes in the same period where possible.

Day 9: Generate the GSTR-1 summary from Tally. Compare outward tax by rate and category against the GSTR-3B working sheet using the table mapping above. Resolve every gap above ₹10,000. Document reason codes for intentional differences (RCM outward, zero-rated exports, advance reversals).

Day 10: File GSTR-1. Download the auto-drafted GSTR-3B from the portal. Compare it against your working sheet, differences between the auto-draft and your books are the second-level check.

Day 11–19: Clear any open DRC-01B intimations from prior periods by either filing DRC-03 or submitting a portal explanation. Confirm that GSTR-2B for the current month has reconciled against your purchase register for ITC.

Day 20: File GSTR-3B using the reviewed working sheet figures. Attach the reconciliation workpaper to your filing records. Archive the GSTR-1 JSON, the GSTR-3B filed return PDF, and the variance explanation sheet.

What To Automate Vs What Requires Judgement

Evidence Requirements For GST Audits And 88C Responses

A GST audit under Section 65 of the CGST Act, or a departmental query under Section 61, will ask for your reconciliation workpapers covering the period under scrutiny. The minimum expected documentation is: monthly GSTR-1 vs GSTR-3B comparison sheet, invoice register with GSTR-1 table classification, explanation for each variance above ₹1 lakh, and DRC-03 challans if voluntary payments were made.

Store these in a period-wise folder linked to each filed return. The department can go back five years under Section 73 of the CGST Act for non-fraudulent cases, and six years under Section 74 for fraud, your SOP documentation needs to hold up for that window.

Related Reading

• How GSTR-2B Reconciliation Works In Tally: A step-by-step guide to matching your purchase register against GSTR-2B, identifying ITC mismatches, and documenting reversals before filing GSTR-3B, the inward-side companion to this outward-supply tie-out. AiA's GSTR-2B reconciliation module runs this match automatically from your Tally ledgers.
• Rule 88C And DRC-01B: How To Respond To A GST Liability Mismatch Notice: Covers the exact portal steps to submit a DRC-03 payment or explanation within the seven-day window, the documentation the department expects, and how to close an outstanding intimation without triggering Section 79 recovery.
• GST Annual Return GSTR-9: What Reconciles At Year-End And What Carries Forward: Explains how the GSTR-9 reconciles your monthly GSTR-1 and GSTR-3B figures, what amendments survive into the annual return, and how to close residual ITC gaps before the 30 November cut-off.

References

• CBIC — CGST Rule 59 (GSTR-1 format and provisions)
• CBIC — CGST Rule 61 (GSTR-3B provisions)
• CBIC Circular 237/31/2024-GST — Amendment window and ITC timelines
• GSTN Help — B2C Large vs B2C Small definition and ₹2.5 lakh threshold
• GSTN — e-Invoicing FAQs including 24-hour cancellation window

Frequently Asked Questions

What is the core difference between GSTR-1 and GSTR-3B in one sentence?

GSTR-1 reports invoice-level outward supply details without any tax payment; GSTR-3B is the summary return where actual GST liability is computed and discharged. GSTR-1 is governed by CGST Rule 59; GSTR-3B by Rule 61. The outward tax declared across GSTR-1 tables must equal the tax paid in GSTR-3B Table 3.1(a), 3.1(b), and 3.1(c) every month. Any difference is a liability mismatch that the portal flags automatically under Rule 88C.

If my GSTR-1 is nil but I have GSTR-3B liability, what happens?

The portal's Rule 88C engine compares GSTR-1 declared tax against GSTR-3B paid tax. If GSTR-3B shows liability but GSTR-1 shows nil, meaning tax was paid but no supply details declared, the mismatch goes in the opposite direction. This does not trigger a DRC-01B, which activates when GSTR-1 exceeds GSTR-3B, but it creates inconsistencies that attract scrutiny during annual reconciliation of GSTR-9. File an amended GSTR-1 in the next period to add the missing supply details, within the 30 November cut-off.

Can a recipient's ITC get blocked because my GSTR-1 and GSTR-3B do not match?

Yes, indirectly. If you do not file GSTR-1, your supplies do not appear in the recipient's GSTR-2B and their ITC is blocked. If you file GSTR-1 but report an incorrect taxable value, causing a GSTR-3B mismatch, the recipient's GSTR-2B carries the GSTR-1 figure, but a subsequent department query on your returns can prompt scrutiny of the recipient's ITC claim. Consistent, accurate GSTR-1 filing protects both your liability and your buyer's ITC.

What is the QRMP scheme and does the GSTR-1 vs GSTR-3B comparison work differently under it?

The QRMP (Quarterly Return Monthly Payment) scheme is available to taxpayers with aggregate annual turnover up to ₹5 crore. Under QRMP, GSTR-1 is filed quarterly, due by the 13th of the month after the quarter, and GSTR-3B is also filed quarterly, due by the 22nd or 24th depending on the state. Tax is paid monthly via fixed-sum or self-assessment challan in months one and two of the quarter. The GSTR-1 vs GSTR-3B reconciliation still applies, the comparison runs at the quarterly level, comparing the quarterly GSTR-1 summary to the quarterly GSTR-3B. The IFF, due by the 13th of each interim month, allows you to upload select B2B invoices so recipients get ITC credit in their GSTR-2B without waiting for the quarterly GSTR-1.

What is the late fee for not filing GSTR-1 on time?

A delayed GSTR-1 attracts ₹50 per day (₹25 CGST + ₹25 SGST). For nil GSTR-1 returns, the late fee is ₹20 per day (₹10 + ₹10). Maximum caps based on turnover apply as notified by CBIC. Late fees cannot be waived retroactively and must be paid on the portal before the delayed return can be submitted. Note that delayed GSTR-1 also blocks recipients from seeing those invoices in their GSTR-2B, directly affecting their ITC.

What happens if I pay more tax in GSTR-3B than declared in GSTR-1?

Excess tax paid in GSTR-3B over GSTR-1 declared liability creates an overpayment. This does not trigger a DRC-01B, which only fires when GSTR-1 exceeds GSTR-3B. However, the excess does not automatically convert to a refund, it sits in the electronic cash ledger and can be used to offset future period tax liabilities. If you want a refund of excess cash paid, file a refund application under Section 54 of the CGST Act.

Can I amend GSTR-3B after filing it?

GSTR-3B cannot be revised or amended after filing. The only correction routes are: adjust the variance in the next period's GSTR-3B, within the 30 November cut-off, pay the shortfall via DRC-03 for underpayments, or carry forward overpayment in the cash ledger. For GSTR-1, amendments can be made in subsequent periods through the amendment tables within the same deadline.

Does an e-invoice automatically appear in GSTR-1?

Yes. E-invoices generated on the IRP are auto-populated into GSTR-1 within 24–72 hours. If the e-invoice is cancelled within 24 hours of generation, it is removed from the auto-population. If cancelled after 24 hours, the e-invoice remains in GSTR-1. In that case, issue a credit note in GSTR-1 Table 9B to reverse the tax impact. Not doing so creates a confirmed outward tax gap in the GSTR-1 vs GSTR-3B comparison (GSTN e-invoicing FAQ).

If I discover a mismatch from two financial years ago, what are my options?

If the error is from a past financial year and you are still before the 30 November deadline for amendments, or before filing GSTR-9 for that year, you can amend via GSTR-1 and adjust in GSTR-3B. If that window has closed, the only option is a voluntary payment via DRC-03, along with 18% interest under Section 50 of the CGST Act from the original due date. There is no other mechanism to rectify a post-window mismatch without interest liability.

Is there a GSTR-1 or GSTR-3B difference that the department never flags?

The Rule 88C flag only activates when GSTR-1 tax exceeds GSTR-3B paid tax. Value-level differences, where taxable values differ between the two returns but tax amounts happen to match, may not trigger DRC-01B but will surface during GSTR-9 annual reconciliation and can attract notices under Section 61 scrutiny. Every value-level difference also affects recipients' GSTR-2B, so there is no “safe” undetected mismatch.