There have been so many busts that had great combine tests that while it helps, since it's a team sport you never know how they will turn out.
Happens to the best of them, Dallas drafted a running back named (if memory serves) Bill Thomas in the 60's, physically he was a near clone of Jim Brown, but he didn't even make it to the team the year he was drafted (if memory serves).
Compare Emmitt's combine to this guy, and you would think if you didn't know better Emmitt would have been lucky to play two years and amass 500 yards rushing, lol....