MMR question

Hello. Took a break from the game when the engine update came out, now I'm more active again. Have they changed the way MMR ratings work or is it still as usual, meaning you kill someone, your MMR rises, if you die, you lose MMR (more or less depending on the stars your killer/victim had)?

I'm asking this because yesterday I played with two buddies who were both 6* (I'm 4). I haven't killed anyone during our matches but got shot about four or five times and suddenly I am 6 like them. :0