R12 Payment Terms
Oracle provided a fix for the calculations for due date and discount date to be the same if the same settings were used.
-If you have a Billing Cycle attached with a cutoff (25) and the Due Date is set for 1 Months Ahead and the Due Dais 15, and the Discount Date is set for 1 Months Ahead with a Discount Day of Month of 10. In this case an invoice with the transaction date of 7/26/2013 should be due on 9/15/2013 with a discount date of 9/10/2013. This calculation is still based on the transaction date.