Why doesn't STT success transfer to MTT.

Same blind levels, same full table to start, but for some reason i can just not cash in any MTT lately while being WILDLY successful in the STTs. Has anyone else had similar varience between the two happen to them? Is this just a patience thing? I seriously can not understand it as i feel i am playing the same exact strong poker in both games, yet have not managed to cash in close to 85% of my MTTs in the past three months. Any help would be appreciated yet none is really expected of such a rant...thanks.

Emon96...stars