Sorry for replying months later! You are not adjusting the mentor (closed loop system) on the dyno. The SERT map is being adjusted. The mentor makes it's adjustments by way of the throttle position sensor, unlike most modern closed loop systems which supply O2 signal directly to the ECM. Therfore the mentor tuning capability is limited in it's capability. To get it right a re-map of the ECM is needed.

This set up is still working great at 30000 miles.