Budget Check for receipt accruals

Hi,

We are on PeopleSoft 9.2. In general, users run budget check for receipt accruals twice-- once during closing Accounts Payable period and again after GL period is closed.

During each month end AP close, following processes are run-

1. Run PO_RECVACCR for receipt accrual

2. Run budget check for receipt accrual-PO_RAENC and PO_RAEXP. Accounting Date Option is equal to the last day of current calendar month.(7/31/2017)

After GL period is closed ( next month), Accounts Payable runs budget check again for  the same transaction types but now the accounting date is the first day of the current month(8/1/2017).

Would like to understand why budget checking for receipt accrual is done twice with different accounting dates.  What fields are updated on running budget check process for receipt accruals.