Actually, there is some controversy on this. We have always put a $0 in box 29, for 15 plus years. We were told to do it that way, by a very large national insurance carrier. They told us that putting in the payment "messes things up". Their example was, if you put in a charge for $80, and show a $20 copay then they would process the charge at $20. Now I know this makes no sense and is an issue in their processing system. BUT, like I said we were told to do it that way, and it hasn't been a problem for 15 plus years. HOWEVER, I do not believe it is wrong (I personally believe it is right) to enter the payment there. So if you are putting the amount paid there, and it isn't a problem for you, I would leave it. We are in the process of switching software systems and our new system puts in the payments.
Michele