That might not be the reason but I'd venture to say the fact that you're seeing best results with pinning means the bullseye style follow through is keeping you from disturbing the gun that tiny bit more for best precision.
Pinning definitely works for me on precision shots too. I'm also less worried about recoil control on long shots knowing that a quick follow up shot is less important than a perfect trigger release.
I've gone back and forth on a slow reset then pausing before firing vs. a continuous reset-press roll and think the reset-pause-press works better for me but really want to get the Apex barrel in my M&P to improve the signal to noise ratio on my precision shooting before I make a decision.