Jerry,
I see a different issue yet the same. The problem is there is no real way to know on the SERT what is 10,20,30,40,50,80,90,100 percent throttle so you are always guesstimating with the SERT. Yet you have the ability to not lie to the ECM / be an extra piece of hardware that could go belly up. You also have some other considerations such as Volumetric efficiencies to tune the bike. The problem is most tuners really arent EXPERTS with the SERT while the PC allows guys to run a set problem and only have to be slightly intelligent to tune beyond that.
the other issue is time it takes to do such a fine tune as the SERT properly costs the dyno guy to much money / time / energy to be cost effective to the consumer.
Hence they come up with Canned maps in the beginning then slightly adjust them to your bike, but instead of adjusting through volumetrics .. they adjust through A/F so the bike really never runs perfect because the V/E isnt right if it were and you changed the A/F to what you wanted the A/F should change too unfortunately in most cases it does not.
-harry