I had the same problem. I moved from PokerStars to Empire to start recieving rake back. I had solid results at Stars in over 1,000 SnGs but at Empire I did terrible and had a small negative ROI.
Basic thing I think you are doing wrong (seeing high # of 4ths) is you are playing to tight when you are down to around 5 people left. At stars you can still be very tight and wait for a hand.
If you let your stack get low at Empire waiting for a hand the big stacks will call your all in and try to bust you as it dosnt really hurt them to make bad calls.
You need to open your pushing requirements earlier in the game and grow you chip stack to increase folding equity when on the bubble.