If you use AAA, you get the discount off the room portion of the package. Only the room rate is discounted. If you get the DDP, you still pay the standard charge for it, but the room itself is discounted.
The exact discount varies, depending on the resort and season you go. But for 8 nights at the Poly during value season, we're saving about $400. Again, the amount is going to vary, and any discounts are only off the room portion of the package.