Dear Jatin
You need to ask your client --if delivery happened in this month & billing can happen ONLY IN NEXT MONTH.
During PGI-if Your Books of Account need to be handled in a manner,
to plan your Costings,followed by other calculations.
Business cannot postpone their COGS planning based on the Customer invoice date.
i will ask one Question: During PGI--stock accounts need to credited to have a clear-cut idea on Exact inventory--other wise Business cannot plan costings,Affects all other customers.
I think you need to educate the client or Inform us what was the exact problem..
Phanikumar