| There are for sure 2 main reason for a higher winrate:
1- larger fish/regular ratio
2- more marginal situations
-1- is pretty obvious. if there 2 fishes and 4 regulars in a game the money of the 2 fishes get divided among the 4 regulars, so the winrate of the reg is half wrt to 1 vs 1. its my impression that a 6max table on average has more regulars than fishes.
-2- hu there are many more marginal situations as well, so the edge of the better player gets enhanced imo (this is because as you say the game is harder).
so i think its natural that if you are a winner shorthanded you'll be winning more HU.
if youre doing so well hu you should also be doing very well when the game gets 3-4 handed, so u might want to check how u r doing from the early positions in a 6max game (utg and utg+1) | 
