N.E.D. is correct. The only discounts on APs are available to:
(1) people who qualify for use of SOG
(2) DVC members and their immediate family who live with them
(3) if you renew your AP you get about $40 off the renewal price (for an adult) but your new pass starts the day after your old one expired even if you wait 2 months to renew it. In that case, it is backdated to the day after the old one expired.
Other than that, there are no discounts to be found for APs.