Can someone explain me how works the points in ranked ?

Hey guys,

Just played two game with a friend and i'm very confused about the RR earned and lost. I don't play a lot (5-6 games per week) and it stuck me always in the same rank for months now.

So to give an example we played 2 games tonight :

First Game : Defeat 9-13
Me : D1 Score 5149 ---> I loose 20RR
Friend : D2 Score 4732 --> He looses 16RR

Second Game : Victory 13-4
Me : D1 Score 4197 --> I get 18 RR
Friend : D1 Score 2804 --> He gets 22RR

So if anyone has a rational explanation, I'd love to hear it...

https://preview.redd.it/3ez2nxgdb43e1.jpg?width=934&format=pjpg&auto=webp&s=438b86265f14c651f7605b67beea23bde2a57209