I though you were creating single purchase invoices with multiple lines? It seems I’m on the wrong track here.
No it just shows the last 20 unpaid invoices, there’s no specific date restriction. Anything falling outside that range would need to have it’s payment logged from the invoice preview screen, you’d then delete the duplicate untagged entry on the bank.
There’s a discussion here that proposes an extension to the 20 invoice limit. We would consider this if it becomes more widely requested.