Sir, when you file GSTR 1 GSTN will compare it with GSTR 3B. This may lead to difference and notice to pay interest You can refer Circular No 7 of CGST Dt. 01 Sep 2017
sir, Interest will be applicable as balance in electronic credit ledger shall utilised towards payment of interest by debiting to electronic credit ledger
I have to check whatever their is any notification for not charging interest for mistakes on GSTR 3B As far as my reading only Late filing fee has been waived vide Notification no 28 Dt 01 Sep 2017