Ok what I was getting at was an initial 2 slot cu mostly likely trained to 3 slot due to the patch. Why so much mana you ask? You are correct in that when they burn mana and go down to around zero that they will launch a goo or low level magic attack as soon as they get enough. However, when fighting bosses like on the roof, the more mana the pet has to attack with at the start, the more damage it will do. The downside side is that you will have to wait longer in between for the mana to rebuild but it's totally worth the wait. Even when training having more mana on the pet is a plus however again, when they burn it to zero during a whisper, you will have to wait longer for it to rebuild which wastes some whisper time.