Another list of factors that seem to have been ignored here is the frontal surface area of the projectile at point of impact, the broadhead's performance through bony, cartilagenous materials, arrow diameter, shaft drag through the viscous materials inside the body cavity, etc....
Hardly ignored! Even so, the jist of this thread has been the advantages of using momentum to predict penetration vs KE. Once again, if all other things are equal......ad nauseum.... Read Ashby's reports and you'll see that he's spends a lot of time testing this other stuff.