A bit after the fact but-in looking at the Mil/Flor game. Between Bush and Johnson each has given up 1 run in 6 starts so combined 2 runs scored in 12 starts. Let me clarify a run was scored against them in the first inning 2 out of 12 times.
The boston game mentioned is or was a bit different. The way I see it the first start for the Angels pitcher and Boston's pitcher has 6 starts and gives up a run in 66% of them.
I am new at this but it appears just another star that has to be in alignment.