when the travel companies release the block of rooms they have held back to the hotel, those rooms usually are deeply discounted for the AP rates.
(travel companies will gain blocks of rooms at hotels to use in packages they offer to clients. if they have not sold off the packages, they give the rooms back to the hotel for their bookings.)
problem is, it's usually a quick 2 weeks to 10 days out when those rooms get put back in the inventory and available to book.
if you booked with the AP for your reservation, watch the website for ap rates dropping for your time period.
call immediately and get the new rate, modify your ressie.
when those block of rooms have been filled, that ap rate can change again.