PBZ (point plank ) is relative to your target.
At the USAMU Sniper School of the 70s there were a lot of Civilian Law Enforcement Agencies attending, including the SS, FBI and state and local Departments attending.
In LE there is seldom the need to engage targets beyond 300 yards (almost never), most were under a hundred. But they had to be ready to instantly engage targets further or closer in an instant.
LE Snipers unlike the military taught to make instant disabling shots (head shots), the military teaches center of mass shooting. I wont go into the whys and what for's, but that's the way it is.
The AMU came out with a Sniper/Counter Sniper guide for LE, in which they made recommendations of rifles and ammo for LE sniper use.
They recommended the 223 in a bolt gun, sighted in for 250 yards, the reason being that with that zero, the path of the bullet was never over 4 inches high or 4 inches low to 300 yards. (55 gr Ball, they didn't have many heavier bullets back the).
Thus if you could make headshots without having to make sight adjustments.
I've taught LE Snipers using this theory and it worked out quite well.
This works in hunting also, regardless of what gun/ammo combination though the zero/PBZ may be different.
You determine what game you're going to hunt. You determine the size of the vital area of that animal, and get your PBZ accordingly.
For example the vital area of an antelope averages 8.5-9 inches. Determine where to zero so the path of the bullet is no more then 4 inches low or 4 inches hide. That would be your PBZ.
On elk the average size of the vital are is 15 inches, so you can be 7 inches low or high without adjusting your sights.
All you need to know is the range to the animal. You can use range finders, MIL or MOA scopes to determine range.
Lets use mils and the two animals above. I can look through the scope of my 270 and instantly determine if the animal is within range of my PBZ. For the Antelope if it is 1.25 mils or larger, its with in range. On elk if its 2 mils or more its within range.
If beyond that, then you have to adjust or hold over. I like to adjust for longer shots as I like to shoot for hair not air.