Accounting Rule

We need to get some conveyance allowance pertaining to FY 2020-21. When submitted details to our accounts department, our accounts manager told balance sheet closed on 31^st May 2021 and hence not possible to release the payment pertaining to closed financial year.

Here, my doubt is when balance sheet closed, they are saying previous year expenditure not possible to process or admissible. If so, how can they book income pertaining to previous year realised after closing the balance sheet. Is accounting system also following discriminatory rules.

Can you please guide.