Account Invoice Discount Amount

This module adds two new money columns to the invoices and bills list in Accounting.

• "Discount Amount" shows the early payment discount in the document's own currency.
• A second, hidden-by-default column shows the same discount in your company currency.

Both values are calculated automatically from the payment term line that grants the early payment discount, so they always match what is on the invoice. The columns only appear when there is actually a discount on the document, which keeps the list clean.

It works on customer invoices, vendor bills, credit notes and refunds, because the discount is taken from the payment term line and keeps its sign (negative on bills and refunds).

The module extends the account.move model and the existing invoice list view; it does not add new menus or screens. Everything is visible from the standard Invoices and Bills list views.