Sure you would, but it still says you will fail more than 7 out of ten times and it still remains a fact that he allows a run every other inning on average. This was one of the other innings.
There are multiple ways to get to a 4.50 ERA. You can pitch an inning a night and give up a run every other one of them. You can pitch 10 innings over 10 games, giving up 5 runs in one of them and 0 in the other 9. And countless combinations in between.