Payment terms in accounting document

Hi,

I need to understand how the payment terms in accounting document for credit notes are updated.From what I understand these should either be referenced from the customer master data or from the credit notes billing documents(since there is a different payment term determined in the credit memos from the original invoice). I need it to be referenced from the credit memo billing documents in all cases but I find in certain cases,these are picking up the payment terms from the customer master data which is incorrect.

let me know how do i proceed with the changes.

Regards,

V