We need this too as it would save us a lot of work. Our current process is to send an invoice within 24 hours of a transaction which is fairly easy to do using the 'Transactions Thru' Date field, however, we really don't want to VOID the previous invoice and send a NEW invoice, when the original invoice is still within the Due Days parameters. 

The process should include an option to exclude all accounts that have an existing invoice where they are still within the due date of the invoice.