Where or who came up with that .36? I think it should be .41693. Even then using a broadhead like a Grizzly or Zwickey and being certain that the arrow is flying straight behind the broadhead is important. Of course, all the numbers in the world will not matter if the archer because of buck fever or an odd shooting situation comes up with a shorter than normal draw.
Reminds me of when I told my wife to not shoot past 20 yards with her 38 pound bow at her draw with 425 grain arrows. She proudly showed me an arrow covered back to front in blood and declared that she waited until the deer was on the closer trail. I thought wow, she shot it at 6 yards. She was referring to the old cow paths on the hill, not the current little deer trails. Her closer trail was 32 yards away, the deer went down in about 50 yards in a clump of cedar shrub.
Reminds me of another one. A big dude, he thought he was a big dude, that shot a 70 pound Herters recurve, kept at me because those Hill longbows did not have enough power to kill a deer. At that time I had a 50 pounder, a 60 pounder and an 89 pounder. He invited me to shoot my 2020s out of both bows as proof. The Herters put out a faster arrow than the heavy bow and that is all the proof he needed, because he shot four deer and never got the arrow coming out the other side. He showed me his arrows, 2219 29" long, swedged both ends and Bodkin heads, they flew terrible and he about gave himself a hernia twisting and torquing to get the bow back. That year, I shot a deer late in the season with a 55 pound Bear takedown, he couldn't have prouder for thinking that he changed my evil longbow ways.