Hi Terri,
I am sorry to tell you that payment term can not be removed from personal setting, and there is no standard way to avoid that users change their personal settings. I have also tried to find user exits,
bu there's none available for your request.
However, the standard model can of course be altered using the BAdI
ME_PROCESS_PO_CUST where you may well implement your own logic, as
desired.
Best regards,
Yang Bai