If you look at the manuals for the Fw190 series you'll see that factory set convergence is not at the sight line. If the factory settings allowed it then it should be modeled in the game.

Also, if the cowl guns were set to be parallel (ie they don't converge) then that should also be modeled as well.
To Krusty's point, I think that in general the cone of dispersion is to small in most cases in Aces High (I don't have any proof). Given that the very best hit percentages ever attained in the US training programs by instructors was about 20%. These were combat veterans (some were aces) that were shooting at a towed target, flying in a straight line, and constant speed (and at close range, 300 yards or less). I just chalk it up to various environmental issues that are not modeled like turbulence, equipment ware (like gun barrels over heating), aircraft rigging, or malfunctions.