Okay, so we talked to them, and their math IS screwy, and they're unwilling to fix it. They're going with a much higher nightly rate now than when Rolf first booked the hotel, so that the total only dropped 20 bucks. So be it, not my wallet to argue over, but it's a poor way to cut a deal. (Katrina disagrees, saying that the rate Rolf initially booked it for was already including the 2 for 1 discount in the price.)