Upgrading passes?

I just emailed WTR about upgrading my passes to VIP.

The responded (quickly) and said that in order to upgrade, I need to buy the VIP pass, then they will refund me the original pass.

So, I've given them $400, now they want another $700 before they'll give me the original $400 back, and I highly doubt they would refund me any of the fees associated with the initial purchase...making the upgrade essentially cost $100 more than it would if they'd actually "upgrade" your pass and not have you buy a new one.

Does anyone know how it works at the box office on the day of? Will they just upgrade for the difference in cost, or do you still have to jump through all these hoops and be out the extra fees.