This is a very good analysis. One potential reason the walks did not come out "right" is that (as best I can tell) SI excluded intentional walks from BB when determining the walk chances on the pitcher chart. For example, about 1/4 of the walks Richert and Dukes issued were intentional, and that appears to be skewing their BB%. I suspect BB% in the game will come close to actual BB% if the BB% is adjusted to exclude IBB. It looks like the BAA you calculated for Jim Palmer for the Game came out very close to what I calculated using a different approach (I'm going from memory here). My theory is that Wins (and possibly ERA) played a big factor in determining the pitcher charts in the original SI game. It's also possible that they overlooked the impact of the defensive outs, which can have a notable impact for a good defensive team like the 1971 Orioles. On a final note, your analysis assumes that the batter charts are accurate, and your previous analysis showed that they indeed are pretty accurate.
