Okay, it looks like there are at least two components to this issue - the first being the Price.
It looks like your statement explains what's wrong at this point, but I'm not sure it explains how it happened. I don't believe it was intentional. The cashier described to me what happened, and it was an absolutely normal transaction. She admits that she may have clicked on one of the Modifier buttons (though that shouldn't have caused this), but she's sure she didn't use the Edit function. I trust her more than most, I can find no motivation for her to have given this person a discount (she was from out of state and had never been in before), and it was a credit card transaction for which the customer simply paid the “discount” price (i.e., I see no way our employee could have benefited).
Besides all that, I don’t see an “Edit Product” in the Activity Log for during the time of the transaction. There is some activity from a previous start to that transaction (it looks like she brought up a Product to print a price sticker, then deleted it - as I instruct them), and some activity including Edit Product from when I was investigating it the next day, but nothing notable for the time of the transaction itself.
I have to admit that I’ve tried all sorts of combinations of things to duplicate the situation, and can duplicate the "seat number" prefix and lack of price on the receipt (more on that later), but haven't been able to duplicate the Quantity change.
But this does bring up the disturbing fact that quantities can be adjusted to fractions. This instance resulted in a loss of $145 – from a feature that I've never been aware of, can't think of how I'd ever have any use for, and could pop up again at any time. Sure, I’ve already asked everyone to look more closely at the Retail/Extended prices, but I can already guess the accuracy with that when we’re busy. Right now I have no reason to believe that it won't happen again.
(cont.)