If any input is left to be taken then the same needs to be taken the ensuing return. And if excess taken or double taken for any Bill, it should be reversed in other reversal column to arrive at the correct input claim.

If any ITC is left to be taken then same should be taken in ensuing return. And if any any ITC is wrongly claimed or double claimed, then it should be reversed in other reversal column immediately to arrive at the correct ITC Claim.

I have suggested to client that invoice must be taken at the time of delivery of goods or services. Because due to this invoice should be accounted within the time limit.
and we can prevent the client from mismatches in GSTR 3B and GSTR-2A