From just watching Hartmann and the opposing punter during Texans games, he does generally punt less distance. That said, raw punting stats are hard to adjust. For example, we've played some sorry ass offenses with great return men. I remember one game when Kubiak was basically squibbing kickoffs because of the fear of return game. If Hartmann had directions to make his punts directional, then that could explain the stat sheet. Also, given our defense and offense, Hartmann probably lack the situations where he really need to boom it as far as he can.
Isn't the solution obvious to everyone now that we have seen what Yates can do, and the balls of Kubiak on the 4th quarter drive... Texans don't need to punt. They will just go for it on 4th down every time.