Fix Terms of
Payment 
Use
As of Release 4.6C, you can configure the cash discount terms that are used when paying the invoice, irrespective of whether a certain period applies. This avoids loss of the cash discount.
You can fix the payment terms if, for example, the business partner or the business transaction as a whole is responsible for the late payment. The field Fixed has been added to the header data on the tab page Payment.
However, if you enter a cash discount amount directly, the cash discount that the system calculates and the fixed payment terms are cancelled.
See also
For more information, see the SAP Library at Logistics Invoice Verification, Cash Discount .