Having a fairly high ranking at the moment, I find that most wins are worth either +8 or +1 to me,, with the dividing line somewhere around 400 points differential. Nothing in between. If the differential is even higher, I may get 0.
Losses are a minimum of -8, and may go as high as -25 or more. So - against the majority of opponents, I have to win 8 out of 9 just to breakeven!