Just saw some general chat with people arguing about the best way to AA XP once Luclin comes. Some people still think it is based on lvl 51 XP, which has not been the case for a long time. I thought it was changed to be based on the con of the mob (to the highest person in the group) and the ZEM. Wanted to double check. Hence the argument: People said AA XP is fastest just to go to max level. Dunno if that is true for all circumstances (gear: raid gear vs. non? places to XP?) If it is still the way I remember it, then trying to AA XP in groups with varying level range is not very practical.
From what I hear they changed it to be based on: The level of the highest person in your group Amount of AAs you have and probably the level of the mob you killed