Quality doesn't matter, if it's close enough. I think, range is around 20-30%. Everything else is just luck and tactic.

Look at this... Chri is a FA member and RL-friend. He is the weakest active manager... but do you think, 5 points to 3.place is only luck? Btw... he made 4 points vs the strongest team, Znan (beside me).
He made 3 points vs 4th (2nd game isn't played)
He made 4 points vs 5th
He made 3 points vs 6th
He made 3 points vs 7th (2nd game isn't played)
and so on.

Click image for larger version. 

Name:	league.jpg 
Views:	145 
Size:	31.6 KB 
ID:	74127

Click image for larger version. 

Name:	leaguequality.jpg 
Views:	145 
Size:	52.9 KB 
ID:	74128