If you book through AAA and book a package, you have to have the balance paid off in full 45 days prior to arrival.. (They actually suggest a few days before the 45 day prior mark so they can ensure that the payment is made to Disney in time.)
We opted to go through AAA as we wanted both the dining plan and the AAA room discount -- can't get both of them through Disney directly, just one or the other. It's the first time we have not booked directly through Disney.