I guess if you are solely hunting for antler size and not maturity then culling has some effectiveness, but if you are only shooting mature deer then who cares what they score. If you think killing one deer is going to make "bigger" bucks come in I guess that's your call to make, but in the last 14 years of bowhunting I've never had a "bully" buck keeping other mature bucks off my area. If they are truly mature (6.5 y/o) they have a totally different demeanor than the 4.5 y/o's. They mainly keep to themselves, are less aggressive, and do less breeding. Go for it skyleralan, but make sure you are killing him because you want to not because you think you need to.