I wouldn't sweat it, there are so many variables that go into penetration in the moment. Equally important to poundage is draw length - 35 lbs at 24" draw is not the same as 34 lbs at 30" of draw. Heck, persistence on a track to me is more impressive than a perfect shot.
you could look at going to some of the micro diameter shafts, they do seem to help penetration in my experience (on game, not just foam or gel). Having the shaft as slim as possible so as not to drag. My kids shoot them - with short draw lengths and sub 40 lbs for 2 of them - routinely blowing arrows all the way though deer.
Or do some exercises with with bow - draw hold - let down. 10x DO BOTH LEFT AND RIGHT HANDS - to avoid neck issues. Think this is something often overlooked by us.