You might have to wait a while to see if an AP discount comes out.
Some discount types (AP and FL resident in particular) are usually announced only one full quarter in advance. So for April 2014 (2nd quarter) sometime in the 4th quarter 2013 it MIGHT come out. Relatively, those are short-time-in-advance discounts to get locals to visit who might be able to plan and visit on shorter notice (FL resident) or can take a lower priced vacation (with AP tickets are already paid for).
If you are shooting for early April, though, be aware Easter falls on April 20 in 2014 (was in March 2013) and the Fort is pretty full and high priced the week before Easter Sunday and the week after so discounts may not be needed. I'd be surprised if there even were any for then.

That's just my personal opinion. How close to April 20 were you looking?
Bama Ed
PS - keep trying though.