It had to do with how much imm xp he got. These were both extremely long lived cabal leader characters. It shouldn't be so surprising when it is revealed how much love they got.

I don't think Vhloughvang was played by an imm, but, he still got tons of love. I personally like it when imms reveal their mortals. If they get more love then my characters I generally believe it is because they know how to play solid characters. I mean, they themselves are the ones who read roles, reward them and the RP/PK aspects of characters. Having this knowledge probably makes them more intune with what their imm colleagues will reward.