I had been doing a lot of research in this area recently and found some very helpful websites.
http://bowsite.com/bowsite/features/...tion/index.cfm
http://home.att.net/~sajackson/ballistics.html
http://www.tradgang.com/ashby/Moment...enetration.htm
After doing lots of math and reading these the best conculsion I have is don't worry about KE or any other figure.
Get your Spine correct, your bow tunned and shooting straight, and the most important part is your Broadhead....it needs to be sharper than a razor blade if you want the best success in the field!