I think we need to go back to the original information. First he has only played in 3 seasons not 4, his rookie year was on IR. Second he has 75 total tackles.
http://espn.go.com/nfl/player/stats/_/id/14019/jarvis-jenkins
I have never actually seen the guy play, but the point remains the same, putting tackles and sacks stats on a run stuffer does not tell the story of their effectiveness. What scheme were they in, where they asked to attack or control gaps and linemen, how many times did they effectively control their gaps, and so on?