Why can't I change prices on a sales invoice?

KB90

Overview

If a Sales invoice comes from a Dispatch record, and therefore ultimately from a Sales order, then Accentis Enterprise will not let you change the Sell price on the sales invoice, otherwise it would be inconsistent with the Sell price on the sales order. Many of the sales reports in Accentis Enterprise use both sales invoices and sales orders to generate their data, and it is important that when you view the prices on a sales invoice, you can be sure that they are the same prices shown on the sales order.

Secondary to this is that fact that if a sales invoice has been issued to the Customer, it is generally not advisable to change the value of that invoice because of auditing and regulatory reasons, so in many cases a credit and re-issue of invoice is required.