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A company selling IT services to 40 clients processes approximately 480 invoices per year. If even 5% of those invoices have a GSTR-2B mismatch — the supplier filed late, the GSTIN was wrong, or the invoice amount differs by a rupee — the buyer faces 24 invoices where claimed ITC does not match GSTR-2B. At ₹1.8 lakh average invoice value and 18% GST, each mismatch represents approximately ₹3,240 in ITC at risk.
Twenty-four mismatches = approximately ₹77,760 in ITC exposure, plus 18% interest from the date of claim. A notice follows automatically.
GSTR-2B vs Purchase Register Mismatches
Error 1: Claiming ITC Before It Appears in GSTR-2B
The most common trigger: claiming ITC in GSTR-3B for an invoice that is not yet in GSTR-2B for that period. This happens when suppliers file GSTR-1 after the 14th (GSTR-2B generation date) or file late.
Prevention: Only claim ITC for invoices confirmed in GSTR-2B. Pending invoices should be tracked and claimed when they appear in a future GSTR-2B.
Error 2: GSTIN Mismatch Between Invoice and GSTR-2B
A supplier files GSTR-1 with the wrong GSTIN for the buyer. The invoice appears in GSTR-2B, but under the wrong GSTIN — and does not appear in the correct buyer’s GSTR-2B. The buyer claims ITC that is not in their GSTR-2B.
Prevention: Validate GSTIN on all purchase invoices at receipt. Cross-check GSTIN against the GST portal’s GSTIN search tool before posting.
Error 3: Duplicate Invoice Claims
A supplier files the same invoice in two consecutive GSTR-1 filings. The buyer claims ITC twice — or claims once but the GSTR-2B later shows both entries, creating a discrepancy when one is removed.
Prevention: Maintain a unique invoice register — no two invoices from the same supplier should have the same invoice number.
TDS Deduction Rate Errors
| Section | Correct deduction basis | Common error | Consequence |
|---|---|---|---|
| 194C | Taxable value only (not GST-inclusive) | TDS on total invoice including GST | Over-deduction, excess TDS — notice to deductor |
| 194J | Professional fee taxable value | Applying 10% to gross amount with GST | Same as above |
| 194H | Commission amount | Applying rate to gross settlement | Excess deduction from platform settlement |
| 194Q | Purchase value above ₹50L | Including GST in purchase threshold calculation | Incorrect threshold — missed TDS deduction |
Error 4: Wrong TDS Section Code in Filing
A company deducts TDS under Section 194C on a software service contract that should be Section 194J. Form 26Q is filed with the wrong section code. The deductee’s Form 26AS shows the credit under the wrong section — creating a mismatch when the deductee claims the credit.
Prevention: Maintain a deductee register with the applicable section code per counterparty, reviewed annually.
Platform Settlement Timing Errors
Error 5: Revenue Recognised in Wrong Period
Platform settlement for December orders arrives in the bank account in January. Finance team books it as January revenue. GST liability is understated in December GSTR-3B and overstated in January — creating a cross-period mismatch that appears in the GSTR-1 vs ledger comparison.
Prevention: Book revenue on the date of supply (typically the date of delivery or invoice), not the date of settlement receipt.
Error 6: TCS Not Separated from Settlement
E-commerce operators deduct TCS at 1% on gross sales before settling. If the TCS is not separated from the settlement credit and recorded as a credit under the buyer’s GSTIN, the buyer has unclaimed TCS in GSTR-2B at the end of the year.
Prevention: Match TCS deducted (shown in gateway settlement statement) against GSTR-2B TCS credit each month.
Other High-Frequency Errors
Error 7: NACH Credit Disaggregation Failure — A bulk NACH credit is booked as a single receipt instead of disaggregating it to individual customer accounts. Interest income or instalment income is then misstated.
Error 8: Credit Note GST Not Reversed — When a customer returns goods and a credit note is issued, the GST on the original supply must be reversed in GSTR-1. If not reversed, the outward supply figure in GSTR-9 overstates actual supply.
Error 9: RCM Liability Not Declared — Imports of services (software subscriptions from non-resident vendors) attract GST under Reverse Charge Mechanism. If not declared in GSTR-3B, the RCM liability shows up as a discrepancy in the annual return.
Error 10: Place of Supply Error on Interstate Transactions — IGST applied on a transaction that should be CGST + SGST, or vice versa, creates a mismatch between the buyer’s ITC (which appears as IGST in GSTR-2B) and the GSTR-3B claim.
How to Prevent Reconciliation-Triggered Audits
The single most effective prevention measure is reconciling GSTR-2B against the purchase register before filing GSTR-3B each month — not after. Errors caught before filing can be corrected without interest or penalty.
GST reconciliation software that automates the GSTR-2B vs purchase register match generates an exception list before the 20th of each month — early enough to correct any discrepancies before GSTR-3B filing.
Reconciliation software India that covers TDS section classification and platform settlement matching prevents Errors 4 through 7 at source, reducing the audit notice probability for businesses with high transaction volumes.
The GST portal publishes the reconciliation procedures and the notice response timelines applicable to GSTR-2B mismatch cases.