I tend to agree with Rack. All to often it's form problems. That said, depends on the attitude of the deer a lot of the time. I have literally aimed at the belly line of deer before when they were wired, it was late in the season etc. I seldom aim dead center unless it's on a slam dunk 6 or 7 or less than 10 yard shot. I will say that as the distance increases beyond 30 and approaching 40 I tend to aim more dead center. A deer at 30 or 35 yards is less likely to react to the shot noise than one at 18.