I haven't found the stick-on thermometers to be very accurate. I use the ones with the suction cups in all my tanks. They're really cheap, maybe you should pick one up.

I would say yes the tank is probably about 2 degrees cooler than what the sticky says IME. You can float some ice cubes or set a fan blowing across the top of the water. I always throw in an airstone (if you don't have one running) just to get the surface moving a little bit to keep the cooler surface water to flow througout the tank. You don't have anywhere else you could move the tank to, even across the room?
Enough saidI could, but its a 90 and a pain to move. I would have to empty most of it and have someone help me slide it