I am doing baal runs with my level 60 Sorceress in Nightmare. My merc is only level 50 and he gets way less experience per run than my main char. To get any levels in nightmare baal runs you need to be level 40. You stop recieving xp at about level 75. My Merc has the perefect range, why doesn't he get that much xp? He is always next to my sorc and should get full xp. Maybe because he is not necessarily in combat, since the enemies die mostly from my spell damage aoe and not from his hits.