It's the first shot that counts! You're doing good there.
My LR/ELR stuff is all single shot. I break position after each shot. Mostly to start and stop the video camera but "usually" shoot only one shot before changing distance when working up drop chart.
There are several things that could cause your predictable flyer. However, if your first two shots are always spot on, make 'em good. Thus no need for a third.
You'll burn out the barrel chasing that 3rd shot.
Heck, when I put the first two together at any range, I stop shooting.
I still feel the remorse from burning out a wonder 270 AM barrel with out ever harvesting anything but rocks.
Sure was fun though. Expensive and disheartening. But fun