One suggestion could be:
Multi-level managers --> YES
Calculate %percentage for cup excluding 1&2&3 star players from team.
If team has no 4+ star players, calculate the 3 star.
If he has no 3 star players, omg what he is doing in top eleven.
In this way multi level managers will play along and quality will be at the same range.
That was Nordeus wanted at first when creating cup, but it seems that quality average calculation needs some refinements.