I think his formula is very simple: wins / salary. A basic return on investment calculation. You can't leave out the fact that there's replacement level to worry about. We should be talking about Marginal Payroll / Marginal Wins (club payroll - (28 x major league minimum) / ((winning percentage - .300) x 162)
AL East Club Marginal Wins Cost per Marginal Win
Least Efficient Yankees 48.4 $3,832,791
Most Efficient Blue Jays 38.4 $1,634,349
AL Central Club Marginal Wins Cost per Marginal Win
Least Efficient Royals 13.4 $2,846,119
Most Efficient Twins 47.4 $1,144,304
AL West Club Marginal Wins Cost per Marginal Win
Least Efficient Mariners 29.4 $2,680,402
Most Efficient A's 44.4 $1,195,655
NL East Club Marginal Wins Cost per Marginal Win
Least Efficient Braves 30.4 $2,664,503
Most Efficient Marlins 29.4 $198,724
NL Central Club Marginal Wins Cost per Marginal Win
Least Efficient Cubs 17.4 $4,900,488
Most Efficient Reds 31.4 $1,648,201
NL West Club Marginal Wins Cost per Marginal Win
Least Efficient Giants 27.7 $2,920,593
Most Efficient Padres 39.4 $1,541,628
Figures taken from Baseball Prospectus The Cubs are obviously the worst of the bunch.