Guys have problems shooting high at close range from tree stands. The basic issue is they fail to lean at the waist, to get their upper body in line with the shot. It's a very common problem actually.
I quit using tree stands quite a few years ago now, and am much more comfortable out to about thirty yards. That said, the last half dozen deer I have taken were well within twenty yards, and the last two within twelve.
Hunting from the ground allows for better access to both lungs, and more pass through shots. And, it's just as easy to get close.