I've only used the AAA discount for our visits to FW. When you call, if your desired dates are available make the reservation even if the AAA discount is not available. As others have stated, you can call later and have the discount applied. There are only a limited number of discounts available per month but folks are always making then canceling reservations. For our last trip I called every week for about two months before I got the discount. Persistence pays so keep trying if you don't get it the first time.