Matchmaking points, how does it work?

I know when you lose, it takes points away in rank and when you win it gives you points. But how do they decide how many points they give or take away because, to me, It doesn’t make sense.

Had one match where we caught the monster stage 1 and took it out. And it only have me 2 points. Next match, wraith made it to stage three, almost killed it, but it still won, and they deduct me 28 points! I feel like that doesn’t make sense. It should be lower the health, the less points you get deducted. And if I kill the monster stage 1, it should give me more points because I was able to catch so early on in the game. Or maybe more points on the stage of the monster. I just don’t get it. Can some explain this to me.

Here is all the info you need.