Sorry I wasn't clear, I was just saying it used to do the % damage, and did stack with different monks, but there was an internal mechanic that scaled the damage down in 2,3,4 player games. Which made sense, 50% of the health as damage (for a monster) in a single player game may be 1mil, but in 4 player, it may be 3mil.

Now it's %weapon damage or whatever, so probably no need to scale anything in multiplayer games.