I did too... when you "exchange" they still ring your original purchase back through at $401 and then your exchanged iPad is $429 unless your BB did something different than mine regarding open item products. The only time they don't charge your full price on an item is if you bought it on sale and then they have to price match it back down to your original purchase price or it might do that automatically. But an open item price is manually taken off.
Maybe I'm wrong... it's been nearly 10 years since I worked at Best Buy.
I see what you're saying. Weird. Our store manager was pretty lax on things like that. I guess maybe they have changed. It's been 8 years for me