4 points is not a lot of difference... 8 points or more, yeah, is difference. And the quality that you see of 16,3 is looking all players of the team because is a promide... sometimes you have to think, and thats my case, that I have a quality of 67 looking all players of my team, (at now I think...) but the % or promide of quality of the 11 players of the field is near 75 of quality...
that's the 1st..
2nd and important...you see 8 players + GK in the field but the game do the simulation with 11 vs 11 all times.
and if you see a team with 5 players too. so really this guy don't have 1 defender.