Message

Credit note line amount MUST be equal to the price amount multiplied by the quantity, plus charges minus allowances at the line level.

Context
cac:CreditNoteLine
Test
$quiet or u:slack($lineExtensionAmount, u:twodec(u:twodec($pricePerUnit * $quantity) + u:twodec($sumCharge) - u:twodec($sumAllowance)), 0.02)
Usage
/ ubl:CreditNote / cac:CreditNoteLine / cbc:LineExtensionAmount