The difference of quality is biggest in levels like L3/L4/L5/L6 for example, when you get all these inactive sides that get abandoned and they still manage to sneak 1 or 2 promotions before not being good enough to advance anymore, this is why you sometimes will see a team with 1* and 2* players when you are moving up through the leagues in the lower part of the game, when you get to L10+ more active managers appear and most inactive teams are deleted out the game by then, so the difference can be less than Q10 between best to worst team in the league, If you exclude my team in my league being Q104 average, the worst is Q88 and the best is Q96, that is a difference of just Q8.