From Mousesavers:
Annual Passholder Room-Only Discounts
Passholder discounts are currently available for check-ins through 6/3/06.
Travel dates: 4/23/06-6/3/06. Discounts are $25 off Value resorts, $40 off Moderate resorts and $100 off Deluxe resorts. Book by 6/3/06.
Travel dates: 2/16/06-4/13/06. Discounts are $35 off Value resorts, $66 off Moderate resorts and $133 off Deluxe resorts. Book by 4/8/06.
So it looks like if you check in April 14 through April 22, you wouldn't have any AP rates available.