Leveling with PotD

[Zojha]

Could be wrong feel free to correct me if i am

And that I will - You get the exact same XP no matter how much you kill in the palace. The same also goes for tomes by the way. What matters is your level outside of the palace and the floor set you are doing. It should be noted that the armory bonus applies, but it doesn't seem any other XP boosts do (although I only tried the ring from the Hall of the Novice).