When I performed 5,6,7 and 8 levels,I had a ML/AML player who didn't grow up his rating so fast ( from 41 to 45) ,but in my classical 4-5-1, he had very good performances against appearently better quality opponents and he scored more than ST players.

Starting from level 9,of course,where I had to face 55 mean quality level MR,I had to sell him.

This means that the performance of a player depends on quality level,but also,age,correct role(native role if he has learned other roles),motivation.

Motivation is the key element: if a very good rated (and also young) player performs bad and improves worst,because he has nothing more to give for the team,I sell him without esitation.