at one point in time it was worth my purchasing an AP just for the room discount for an 8 day trip.
now, Trotsky is correct, the GP and AP discounts are so close, there is no real difference in price. so during years when i am not sure i will make it there twice, i do not plan to purchase the AP.
and the GP discount comes out way before
i do what you do, book without a discount, then....
switch to GP discount when it comes out, then...........
switch to AP discount if it is any better.
the mouse savers link is useful, tells me when to start checking the site frequently- meaning- several times a day for the discount to come out