Down Payments and Cash Discount
If no cash discount has been taken into consideration in the down payment, you can post the cash discount when you pay the closing invoice. The cash discount base is generally the invoice amount.
If you deduct cash discount when you post the down payment, you must take this into account when you post the closing invoice. This means you must reduce the cash discount base amount by the down payment amount. Cash discount is then only granted on the remaining amount.