Received a GST ASMT-10 scrutiny notice for FY 2023-24 on a GSTR-3B versus GSTR-1 mismatch. How should we reply?

Start with a line-by-line reconciliation for the year: GSTR-1 as filed (including amendments in later months), credit and debit notes, and GSTR-3B table 3.1. The usual explanations are credit notes reported in GSTR-1 but netted in 3B, invoices amended in a later period, and supplies reported in 3B in one month and GSTR-1 in the next. Present it as a table that bridges the ₹14 lakh, attach the GSTR-1 and 3B summaries and the credit notes, and keep the covering explanation short.

If part of the difference is genuine short payment, pay it through DRC-03 with 18% interest before you reply and say so. Paying before a show-cause notice under section 73 means no penalty at all; paying within 30 days of the notice also avoids penalty, after that it is 10% of the tax.

Time limits work in your favour: for FY 2023-24 the officer must issue any section 73 order within three years of the annual return due date, that is by 31 December 2027, with the show-cause notice at least three months earlier. If the reply is rejected you will receive DRC-01A first, which is another chance to settle, and an adverse order can be appealed within three months with a 10% pre-deposit.