3181226 - PO Charge Amount Variance fires even with no charges on the invoice

We want the charge amounts on invoices to be reconciled against the Purchase Order (PO) on a per-invoice basis, rather than totalling the charges on all invoices against the PO.
Therefore, for the PO Charge Amount Variance exception type, we originally changed the Field Path to Validate from Order.ChargeAmountInvoiced to ChargeAmount.
However, when the supplier provides no charges on the invoice, the exception still fires.

POChargeAmountVariance , KBA , BNS-ARI-INV-IR-EXP , Invoice Reconciliation Exceptions , Problem