I have never used EFOC, but have used both heavy and light arrows - and if anything - I have found that the lighter faster arrows penetrate better in both bone and flesh on whitetails anyway.
and that is precisely what your missing in the ashby studies.......no one.......no one......in the traditional world has done more detailed extensive field research regarding arrow penetration in the media we hunt than ashby.........forget plywood......phonebooks......balistic gel........trashcans filled with sand..........your test used basicly normal low foc in both arrows..........one would expect that shot from the same bow the results would not show much measurable difference in penetration.......and since whitetail are really not that hard to penetrate............duh......
as the ashby studies show..........it's when you go to extreme foc 19.....23...+ % in foc.........the point is reached where no light normal foc arrow will match the penetration using the same p behind both arrows. ashby's work is indisputable in pointing out what a high foc heavy arrow can achieve versus a light normal foc arrow when shot from moderate weight bows. there is no comparison.........do you need a high foc arrow to kill a whitetail......of course not........but the goal should be.......to hunt with the arrow weight efoc broadhead combination that offers the best odds all the time of deep penetration when shit happens..............
that in a nut shell is the simple equation that the ashby study gives to everyone..............if they choose to use it.
your test in no ways matches what his work so arduously points out time in and time out. a heavy efoc arrow will eat your light arrow from the same bow.......day in and day out............in the bone flesh and blood we chase................is it necessary to have........no.......but it's just one hell of an insurance factor going down range when things go wrong with the shot.