I am not the best shooter on this forum, nor am I the most qualified to advise anyone on handgun-shooting technique. Despite what I just said, I can easily comment on your last post. Having a low or high target, at relatively close distances, is sort of irrelevant. The question posed to you had to do with your point of impact (POI) in relation to your point of aim (POA). In other words, when you aim at the bull's eye (regardless of the height placement of the target itself--high, low, etc.), where do your shots hit the paper?
There are many factors that contribute to a miss, including errors in grip, stance, aiming, and trigger pull.
If you are hitting to the left of POA (and you are right-handed), you might not have enough finger on the trigger and are in effect pushing the trigger, and consequently the gun, to the left as you pull the trigger. You may have too much finger on the trigger or even the right amount but are rolling or hooking your finger as you press the trigger rather than pulling it straight back toward your nose. The only part of your body that should be moving when you pull the trigger is your trigger finger--and only its last two phalanges, from the middle joint and beyond with no movement at the knuckle joint.
If you are hitting to the right of POA (again, right-handed), it is most likely that you have too much finger on the trigger (actually wrapped around the trigger) and are pulling the gun to the right.
The trigger should contact the middle of the distal pad of your index (trigger) finger. You may find it best to be slightly left or right of the pad's center, but the portion of the finger used to pull the trigger should still be roughly the center of the pad.
If you are hitting low, you are probably flinching in anticipation of recoil and muzzle lift.
Other pointers: With autoloaders, keep your hand high on the pistol. Doing this minimizes the distance between your shooting hand and the bore's axis. The greater the distance, the more leverage the recoil will have against your hand. With a two-hand hold, don't simply use your weak hand to support your shooting hand but use it to grip the gun. The more hand to grip contact you are able to achieve the better. So don't have your left hand hold your right, but get the heel of your left palm onto the left side of the pistol's grip between the heel of your right palm and the tips of your right fingers. Your left thumb should be parallel to the barrel and should be resting on the frame of the gun, above the trigger guard and under the slide. Your right thumb should rest on top of your left thumb's first joint (or there about).
The middle, ring, and pinky fingers of your right (strong) hand should be in tight contact with one another, with the middle finger right up under and against the bottom of the trigger guard. Your left (weak/supporting) hand's fingers should be right on top of your right's, with your left's index finger under and up against the bottom of the trigger guard.