CII-SR-189: Line discounts and charges must not carry a unit basis amount

What it means

Each discount (BG-27) or charge (BG-28) on an invoice line is checked for a UnitBasisAmount element, an amount per unit that the discount or charge is calculated from. EN 16931 allows only a base amount (BasisAmount), the amount a percentage is applied to, and not a per-unit figure.

Why it matters

This is a warning, so the file is still accepted. The per-unit figure is ignored, and the buyer's software works only from the amount, base amount and percentage that EN 16931 defines. It is worth fixing for a clean result.

How to fix it

In the XML, find the UnitBasisAmount inside the line's SpecifiedTradeAllowanceCharge and delete it. If you want to show what a percentage was applied to, put that amount in the BasisAmount of the same discount or charge. Make sure the stated amount is the final figure for the line.

The rule as published

UnitBasisAmount should not be present

Where this rule applies