I would have gotten to the airport at the same time for the original departure since you were getting conflicting information and had an important appointment I could not miss. I understand the ire of having to wait longer at an airport but I rather that then miss a flight I really had to take.
The chances of AA reimbursing the $800 may not be in your favor since they can argue that the automated service stated an on-time departure. Further, AFAIK check-in cut-off is not moved so you still had to be there by the bag drop cut-off based on your original flight time even if a flight is delayed since a delay of 30-60 minutes can be reduced or like in your case eliminated if whatever caused the delay (like lack of a slot) is resolved.