Another note:
The BB-Reference version of WAR, which uses a formula that is only slightly tweaked from the FG formula, has Lester and CC at the following values for the last three years:
Lester: 15.4 WAR
CC: 16.2 WAR.
0.8 WAR difference for a formula that's not supposed to be accurate to the decimal level, all the while including Lester's worst full year at the MLB level, and Sabathia's best.