the factory AFM is also scaled to the factory inlet system, interfering with the inlet system (CAI's, POD's etc) dramatically affect this scaling, so its not a black/white science of modification.
its a main reason why a lot of tuners prefer MAP/BAP with
IAT for tuning, eliminating the AFM for the inconsistencies.
although the AFM scaling can be overcome (ie. VERSO) its certainly not recommended to experiment with new inlet setups unless you are monitoring AFR's or EGT's.