BR-27: A line has a negative unit price. How to fix it

What the rule checks

The rule checks the item net price (BT-146) on every line: it must not be negative. A price of zero is allowed.

Why files fail it

• A discount was entered as a line of its own, such as Discount, quantity 1, unit price −50.00. The total comes out right, but the price is negative.
• A return, a deposit refund or a credit for a single item was expressed as a negative price instead of a negative quantity.
• The software carries a negative amount from the accounts into the line's price field.
• If only the price was made negative and the line amount was left as it was, the report also shows the warning PEPPOL-EN16931-R120: the line amount no longer equals quantity times price.

How to fix it

1. 1Record a discount on the whole invoice as a document-level allowance (BG-20): a positive amount (BT-92), a reason (BT-97), and the VAT category (BT-95) and rate (BT-96) of the lines it reduces.
2. 2If the discount applies to one line only, it belongs to that line as a line allowance (BG-27) with a positive amount (BT-136). The unit price stays positive and the line amount goes down.
3. 3For a return or a refund, keep the price positive and make the quantity (BT-129) negative. The rule is about the price only; a negative line amount (BT-131) is not forbidden by it.
4. 4In our form a discount on the whole invoice goes in the "Discounts and surcharges" section: type "Discount", the amount as a positive number, and a reason. Our form does not produce an invoice with a negative unit price.