Some friends of ours upgraded to a suite when checking-in to the BWI. They were able to get a small discount with AAA, I think it was 10% off. I haven't heard of anyone getting an AP discount on a suite.
ASK! Most persons (general rule) NEVER ask for a complimentary upgrade. So, by all means...ASK. It never hurts, and your request could be "magically" granted. Such things happen daily, in the kingdom of the mouse.
I have AKL cocnierge booked on DVC points, so basically I'm paying rack rate. I did ask, and if there is a one bedroom available, the concierge told me it would be $155 more per night.