It's interesting to run through a cfm calculator of a 446 at 4000 rpm to get 567 cfm at 110% ve and see the dyno sheet at at 118% with a lower cfm number of 556.
Do they backup their Wideband a/f with another one? Sometimes the sensors are off by quite a bit due to being dropped or fouling. . I back up my dynojet WB with a Motec WB when looking for missing power and tuning.