I think it is mainly because it re-allocate the voting power. Such that a lot of minnow who was giving more power ( I read the post which is X4), and that's why your post payout got so much higher after that. I think that is cool for minnow. I am not sure about the effect of the payout for big big whale. But it seems that the payout for every minnow is raising.
RE: Steemit Before and After Update Price Analysis