According to Mousesavers you can only get the room only discount and not on the packages. That stinks. I currently have a package booked but wanted to upgrade to the Contemporary but all allotted rooms for the package are gone. If I want the Contemporary I have to cancel my current package reservations and re-book.
We went to our local CAA/AAA office last time and booked our package there, we saved a bit compared to other packages but got lots of perks like the 10% off in Downtown Disney. Which meant less shopping in the parks and more in Downtown Disney.