FOB Documentation and Discounts

Question posted by Tracey Wallace

Hi All

We are a UK Company selling FOB out of China to a Company in Eire.

They have requested that the Commercial Invoice for Customs Clearance shows the 5% Discount that is allowable to them.

In 15 years, I have never been asked to show this.
Is it legal? What is the best way to show it?
Many Thanks