The 40 times that you are refering to are not accurate at all. There was a article (I believe on ESPN.com) awhile back on the 40 time. They took the tape from the 10 fastest 100 meter dashes in history and looked at what their 40 time was. The fastest was around 4.48 I believe. So when you hear of this recruit ran a 4.4 and this one ran a 4.3 know that it is hand timed and also on the recruits start rather than a gun start.
Rocket Ishmael was credited with a 4.18, 40. I believe he did that in his NFL tryout.