CII-SR-392: Leave the unit basis amount out of invoice discounts and charges

What it means

A discount (BG-20) or charge (BG-21) on the whole invoice contains a UnitBasisAmount element, an amount per unit that the discount or charge is based on. EN 16931 describes how a discount or charge was worked out with a base amount and a percentage, not with an amount per unit.

Why it matters

This is a warning, so the invoice is still accepted. The buyer's software does not read UnitBasisAmount, so the figure is lost on their side. It is worth fixing if the buyer needs to see how the discount or charge was calculated, or if their system is strict about extra elements.

How to fix it

Remove the UnitBasisAmount element. If you want to show how a discount or charge was calculated, fill in its base amount and percentage instead (BT-93 and BT-94 for a discount, BT-100 and BT-101 for a charge). If the element keeps coming back, check the export settings of your invoicing software.

The rule as published

UnitBasisAmount should not be present

Where this rule applies