ibr-066
An Invoice MUST contain maximum one Payment Card account (ibg-18).
What the rule checks
As the rule set's publisher wrote it. The rule runs on every element the context matches, and fails where the test is false; the validator reports the line of that element.
/ubl:Invoice | /cn:CreditNote
count(cac:PaymentMeans/cac:CardAccount) <= 1
Checked with PINT SG Invoice, PINT SG Credit Note, PINT JP Invoice, PINT A-NZ Invoice, PINT A-NZ Credit Note, PINT MY Invoice, PINT MY Credit Note