Invoices DFF validation when Create Credit memo

Summary:

Hi,

We need to validate AR Invoices DFF values while users creating credit/Debit memo so the system can show the user if this Credit/ Debit memo are valid or not against the related invoice based on the DFF Value For example We have Invoice No100 with amount 5000 SAR and it has been collected (has fully or partially settlement) so when the user try create any credit / debit memo for that Invoice the system can stop the transaction and raising a message to user indicating that this invoice has been settled and not eligible to modify based on the DFF