The other issue with the proposed solutions with respect to the original question is that the payments do not actually list the invoice. Sure, they are grouped together assuming the payment always follows the invoice in a timely fashion, but that's not real life (at least in the AEC industry). This makes it very problematic to use in a spreadsheet or any non-manual workflow..
We "match" all payments to invoices so that information is available. The invoice # should be included in the example reports for payment line items.
