My issue with this is on a whole different level.  I have an HOA client.  The Board has set a policy that payments go to the oldest invoices first. If severly past due clients pay using quickbooks they get a reciept that says they've paid invoice X, when we are required to apply it to the oldest invoice.  As our only remedy for deliquent accounts is to eventually have to file foreclosure, and these records end up in court, quickbooks payment system sets up conflicting legal exhibits to a judge.  In addition, in order to secure loans (because of past due accounts), lenders for HOA have a percent restriction on past dues over 90 days.  Say I have a customer who is 180 days past due but has started making payments. They pay the most recent invoice.  My invoice aging does not improve although the customer is now making ontime payments.  In fact my aging gets worse and worse. I work with other softwares that ask in set up how to apply payments recieved.  The customer pays "on Account" and the software automatically applies the payment based on the companies policy.  Doesn't seem too hard.