The policy on this seems to change from year to year. Currently, my understanding matches yours; that if you book the same hotel as the ABD yourself for pre-days, that airport transportation will be included. I don't believe the same is true for post-days, but as I said, it's a moving target. I agree that talking to an ABD Vacationista is the best way to get the answer for each person's particular situation.
Sayhello