To produce an accurate payment run for end of month is not possible if certain invoices have already been paid. If a report is run to end of previous month, any invoices that have been paid in the current month will still show as unpaid. This can lead to an invoice being paid twice.
The other issue with the aged creditors report is that, when completing 'Payment Terms' for a supplier, if you select 'End of Next Month' the creditors report will default to 30, 60, 90 days.
There does not appear to be any way of overcoming these issues.