Onslaught Points - how are they calculated?

Is there ANY transparent explanation, how much one gets Onslaught points and how many one is losing? Any maths table? Anything solid? And what is exactly the change from Bronze to Silver?

What I really don't get: you do ONE mistake and lose a game -> directly costs you 35 points.
You do SEVERAL important moves and win the game, you get like 22 points.

Do I just have to farm from behind damage? Or kills? Or use rhm and just spot the whole time? What gives u those bloody points? I am tired of winning and not getting forward, because in the defeats my team just instantly explodes, I don't even have a chance to farm the enemies.