Cody,
The problem is, it's not ALL clients that have a PDF. I really prefer for our business, that when my staff create a "time" invoice, they just hit a "Upload" button that can upload a PDF for this invoice and that, the client, if he WANT it, he can connect on the client interface and download it. Most of the time, client don't need it but if we don't give them a way to get it, they need to email us asking the document and that cause us delay for the payment.
I have no problem to pay Blesta for this custom plugin.