Growing up the hi shoulder shot was explained to me as the area of a nerve bundle that when hit results in near immediate incapisitation!
I don't know how true the nerve bundle theory is, but of the hundred or so deer I have shot, the hi shoulder shot puts them on the ground consistently reliably and with authority.
As I said earlier, look at the bones on a deer in the shoulder area. The spine makes a dip at where the the shoulder would be, behind the shoulder blade. The front legs are not attached in a ball and socket as the rear legs are, there are shoulder blades and meat, no real "shoulders" a bullet from a hi velocity round will have enough authority/energy/shock to break the spine, ribs and or shoulder blades and send shards of bone into the lungs and check cavity. One does not need pin point accuracy, I would venture a 2-3"area wil net identicle results. A little lo will still result in leg bone/lungs/heart maybe spine. Back a little will get you better shot on the lungs and the spine. Too far forward still likely get you the spine and if so bone shards radiating out. Too high, well this is a bad shot and will likely allow the game to flee with a bad wound.
A deer shot hi shoulder will be dead as if turning off a light switch. I have seen many suck there legs up to there body dead in mid air.
I have shot more than I like in the heart. Altho never lost one shot there, they ALL ran long and hard. Heck lung shot deer haven't gone as far!
I like shooting major bones but I also like heavy for caliber bullets and large diameters at close ranges.
CW