MMR is the variable that determines how points are awarded for a win/loss.

If my team was 800 rated, but we play at a 2300 level, then our MMR (match making rating) will both pair us up against other 2300 MMR teams and award points as though we are a 2300 team, regardless of where our team rating is at. ie: A team at 2200, but with a 1200 MMR (pretend they've been playing like total crap for a week) beats me... I would lose huge points. Basically... a 1200 team just beat a 2300 team.... huge upset so huge points.