Ha, that's way too much work.
My point is that the manager does have a lot of these calls to make. In the old days they called it playing the percentages, and I believe that's still largely the case. In some cases the percentages may only be 55/45 in favor of a particular move. Nonetheless the manager has to have a rationale for each decision. He doesn't just change pitchers or use pinch hitters and pinch runners arbitrarily, does he.