.27 is a big difference when you're looking at a rate stat over a large sample. If it's one team, then I'd agree with it. But with that sample you're factoring in the average scoring of over a quarter of the league. You're sampling 1296 games. Averaging .27 more per game per team in a division means 175 runs. If that's insignificant, well **** you need some statistics 101.

Of course what I mentioned as well didn't factor in park factors.

This argument of yours is stupid because we have stats that normalize a pitchers performance. They're called minus or plus stats. ERA+ or -. FIP- xFIP- wRC+ OPS+ etc. Even you should know the relevance of these statistics. We don't have to guess if a 2.9 ERA for pitcher A is equal to a 2.8 ERA for pitcher B.