I have some minimal experience in regulating barrel to barrel POI from my conversion of a 20g to 28g. In my several correspondences and phonecons with Kirk Merrington, and others that have done it, they cautioned me to shoot the gun off-hand only for evaluating the POI. Their opinion was that the resistance of bench shooting the gun was different than off-hand, which could result in different POI. But, since I have never shot for POI from a bench vs. off-hand, I can't provide any direct experience there.