Any difference between using GL Period versus PA Period out of the Cost Distribution Lines All table

 We have been up and running on Oracle for about 18 months now.  We are having issues with reconciling job cost (we are a commercial construction company) to the general ledger.  We know this is due to accounts payable invoices and closing issues where the invoice may be entered into one month for PA (usually the next month), but gets posted in the GL to the open month (so an end of month situation).  The result in PA is that the PA Period is different from the GL Period in the table records.  We are having a discussion about which