Hi again,
For accounting purposes, hmm. You could create a 'discount' line item on the SOP invoice and enter a negative number. This would give you the ability to assign it to a different gl account, as well as making it visible. With a little VBA magic, you could get it to automatically calculate the amount based on the invoice subtotal. If the percentage changes, you could still use VBA to read the customer card (or wherever) and grab the percentage.
Kind regards,
Leslie