BR-15 — Missing amount due for payment
What it means
The amount due for payment is missing. This amount is what the buyer actually has to pay — the total with VAT, minus any prepaid amount, plus rounding (see BR-CO-16).
How to fix it
Check that the LegalMonetaryTotal section has the PayableAmount field
filled in. If the invoice has no prepayment or rounding, this amount
should match the total with VAT.
Example
Wrong: the PayableAmount element is missing.
Correct: <cbc:PayableAmount currencyID="EUR">605.00</cbc:PayableAmount>.