The fall discounts are typically not released until July or early August. They are based on availability issues, so hotels that are booked pretty full won't be included. You have two options.
You can go ahead and book a room only reservation now at the resort of your choice and HOPE you can apply an AP discount . . .
or
You can wait until the discounts are released and see what is available at the discounted rate, knowing you may not get your first choice of resort.
In the past, the discounts have been roughly anywhere from 20% to 45%, but that too, is subject to change at any time. There have been times when only the Epcot deluxe resorts were discounted, so the discounts can be very specific.