The changes in GSTR 1 and GSTR 3B for particulars relating to output tax liability, credit or some rectification and amendment can be made till earlier of following dates
Due Date of filing GSTR for the month of September i.e. 20th Oct or
Due Date of filing GSTR for the second quarter following the end of the financial year i.e. 31st Oct
Which means the changes to be made in GSTR 1 and GSTR 3B have nothing to do with time limit of GSTR 9. But, all three GST returns are interconnected, because, the changes so made shall be duly reported in the annual return to be filed till 31st December.
If you have wrongly recorded interstate sales as intrastate or vice versa the same is known as wrong disclosure of place of supply. The same needs to be corrected in GSTR 1 itself. Through,
But, the wrong disclosure of place of supply must have impacted payment of taxes. For correcting the same, you are required to
If the rectification has been done in the due period as explained in the previously , it shall be disclosed in annual return to be filed. For Example if changes for FY 2017-18 has been done till Sep 2018 they shall be disclosed in Table 4K/4L or Table 10/11 of GST annual return to be filed till 31st Dec. The law does not provide any direct route to directly make changes in GTSR 9.
The error made in GSTR 1 or GSTR 3B shall be rectified in respective forms only. No rectification can be made in GSTR 9 annual return. But the changes so made relating to the relevant financial year shall be duly reported in the annual return yet to be filed. Which means, if you have made some mistake in GSTR 1 or 3B from July 2017 to March 2018. The correction can be made for it till Sep 2018. And, the changes so made are required to be reported in annual return till 31st December 2018.
Wrong recording of sales to incorrect GSTIN shall be amended in Form GSTR-1. It shall has no impact on values to be reported in the Annual Return.
Reconciliation statement in GSTR-9C requires auditor to comment on the differences between books of account and GSTR-9. This indicates that the annual return has to be filed before GSTR-9C so that auditor can prepare and submit the GSTR-9C.