There are AAA TAs and there are AAA TAs. For example, if they are out or on vacation, typically no other TA would touch your rez unless the TA authorized it ahead of time. And then, most other TAs would be reluctanct to make any chances.
With AAA, you can book a room-only (with 15%-20% discount from rack) or a package (with the same approx discounts but only towards the room portion of it). The package would be exactly the same as going direct thru Disney.
Now, if you do a room-only rez, you could purchase tix via AAA for a small discount (usually 5%).
As an example, here's what I experienced with last week's GA code. I had a hold rez with AAA. The TA told me she would be out all this week, and last thursday. But she noted on the rez, that any other TA could make changes to the rez. Now, GA came out on Thursday. At 6:45am that morning, I got an email from her that she applied the new promo (note that she was still out that day!).
However, when later I called in to upgrade from ASMu to CBR, a 'reluctant' TA did the change, though she insisted I should talk to my TA when she would be back.