Apparently, Holland & Holland disagrees with gunman re shotguns shooting to point of aim. From Vic Venters' book "Gun Craft", chapter entitled "Hand-Regulating Chokes"--which is based on a visit Venters made to H&H, and an interview with barrel guru Steve Cranston:
"Cranston's ultimate goals are to ensure that the gun prints its patterns to point of aim . . ."
Further on, same chapter: "At the most fundamental, Holland's entire barrelmaking process--including Cranston's careful choke regulation--does assure that the chamber, forcing cone, bore, choke cone and parallel are all concentric with one another and that both barrels will print where pointed when fed appropriate loads."
If the right barrel typically throws its pattern high and left of center at 25 yards and the left the opposite, then the patterns from the two barrels would be farther off in their respective directions at 40 yards . . . and it'd be a bloody miracle if you hit anything, especially with a tight choke (which you start to need at that range). That is, unless the distance from point of aim is only very slight, so that the patterns mostly overlap, even if not perfectly.
And if shooting to point of aim isn't what we should expect to get, then those who use try guns and pattern plates to do a fitting must be wasting their time.
Obviously, shotguns aren't rifles, and the spread of a pattern will compensate for relatively small divergences from point of aim. But they'd better be really small at close range--one standard distance to evaluate barrels shooting to point of aim being 16 yards--or they're going to become pretty significant at longer range.
