He would have out-scored me by 203 points but I would have had 56 more points against. It seems hard to justify giving me the playoffs because of more points against when he outscored me by 4x the difference in points against.
I don't know how common a situation like this is but the fact that it was 5 points in week 10 away from happening makes me wonder. Points Against does not say anything about what your team actually scored or how those points were distributed. A few blow-outs can inflate points against and one would be rewarded for, potentially, games where they score 50 points to their opponent's 200 being more valued than a loss of 99-100. Both losses count the same for the two players in their W-L columns but hard for me to justify the guy who scored 50 points getting the tie-breaker because of a game he was blown out in.