When you tune a bow, you are tuning it to you. You are making up for errors in your form or release. He obviously shoots different than you do. Having the draw a bit long doesn't help, it induces torque in most cases.

Also grip pressure plays a big part in tuning and where your arrow impacts. In order to bare shaft and paper tune with decent results you need to have a pretty consistant grip. Everyone torques a bow, just to different degrees. Where you place your hand and how relaxed it is has a big effect on this. Next time you bare shaft tune try changing your grip or holding the bow tighter, you will notice you impact points shift.

Chances are he just grips the bow differently than you do is all, so the bare shaft went in a different direction. Fletchings do a lot for an arrow as far as forgiveness goes.

Paul