We process 30 invoices a day.  So your answer is to not bill an estimate and instead to copy everything into a new invoice so it can't be found by the link button when we search it and create hours of data entry.  Who is going to pay for all of that lost productivity? If I'm doing that why don't I just go back to carbon copies?  I have an idea how about you Beta test your upgrades so your customers don't have to be the software Ginny pigs?