I just re-read my post and think I should say something about mid range also. When the bullet reach's the highest point in it's trajectory, it has reached mid range. When sighted in at an 8" target, at mid range the bullet will be 4" above the line of sight. If you raise the sight's 2" to compensate for a target beyond MPBR, the bullet will rise more than 4" at mid range missing high.

You are right that the bullet passes thru the line of sight two time's but remember that the line of sight is seen as the center of the target we're shooting at, not the bullet path. It's bullet path and target size that determine's MPBR.

MPBR is determined only by the ability of the cartridge, not the shooter. The shooter's abilities to hit vary depending on the shooter and that has nothing to do with MPBR.