Eddy, you'd do better reading about it on the MS site, 'cause dang if I can explain it. AutoTune doesn't set the AFR and Ignition tables - you have to enter your own target numbers for AFR and Ignition in their respective tables first, but it adjusts the VE (volumetric efficiency) table so the EGO control circuit(which reads the wideband o2 sensor) doesn't have to hunt so far and wide to hit the AFR targets.

A simple way of explaining it would be that when the VE parameters are "in the ball park", the o2 feedback can be more accurately adjusted through EGO correction control.

The table uses the same X, Y rpm and manifold pressure bins as the AFR and Ignition tables, but is expressed as the efficiency (I think) of the engine at the data points.

Does any of that make any sense?

Frank