Simple physics, (is there actually such a thing?), will tell you that heavier has more energy imparted upon impact than lighter...
For example:
Throw a golf ball as hard as you can at someone standing 10 feet away, and they will be pissed.
Now throw a hardball...
Now throw a softball...
Now throw a 16 pound bowling ball...
Golf ball moving fastest does little- if any- physical damage, but the bowling ball will knock him down, (I will neither admit nor deny using a bowling ball as a defensive weapon), and likely break bones, (if the guy is stupid enough to stand there while you toss these things at him).
Hyper velocity and most high velocity ammo does so by way of very light bullets, which slow down upon impact much faster, hence less penetration. I have seen ground hogs hit with HV ammo that never reached the vitals.
High velocity are usually lighter, same end effect.
Standard to Sub Sonic velocity are heavier and slower, so more energy is imparted giving them greater penetration, and they slow down, well, slower.
I shot a ground hog with the Aguila SSS at about 70 yards, and it went through his head and kept going, never did find that slug.
Just one Old Vets experience and opinion...