level 1: ave quality 25 (5 stars) vs ave quality 5 (1 star)
level 9: ave quality 60 (5 stars) vs ave quality 40 (1 star)
for level 1 match, home team's quality is 400% better than away team. for level 9 match, quality is only 50% better than away team. but in terms of star difference (4 star diff), and quality point difference (20 pts diff), the difference is the same.
assumption is that formation and tactics are same for all 4 teams.