Score has nothing to do with your Elo. You have an amount of Elo points, lets say 3000 at MG1 And you will need 3300 to get to MG2. Every match you win you get an amount of Elo points depending on how big you won, if you won 16-0 You get more Elo than if you won 16-14. Same with losing, you lose more Elo if you lose 0-16 then if you lose 14-16. It has nothing to do with performance, not in Valves MM. In Faceit and Esea its all about winning and having a good ADR.