This is a guess based on pure speculation. I can see it going two ways.
Possibility 1:
ABD groups will spend more time at Walt Disney Studios/Archives
Possibility 2: ABD groups will spend the same amount of time at Walt Disney Studios/Archives and then go
Disneyland Resort. In Possibility 2, the group arrives in Disneyland Resort and may get to spend more time in the park. If they want everyone to enter the park together, maybe people have more time to hang out in the hotel or explore Downtown Disney.