It's like hearing a commercial jet fly over and you first look up to when you heard the sound but your eyes tell the brain it's in a forward position. Thus, your brain then points to the acutal plane you see and not where you first heard the sound.
I hate to tell you this old son, but this theory of yours doesn't hold up.
Our ears don't hear where a sound is heading - NEVER - we hear the sound at it's source.
And that is why when we hear a high altitude jet passing overhead, the sound seems to emanate from bbehind the plane. The sound is heard where it came from, not where it's going. While the sound was travelling to our ears, the plane continues flying. Since the speed of light is essentially instantaneous at these distances, and especially in comparison with the speed of sound, we see the plane whre it is at the moment the sound reaches or ears, which is a different place than it was when it's sound started its journey to our ears.
OK, now just what the hey you think this has to do with the percieved direction of the shot(s) fired that day in Dealy Plaza completely escapes me.
People would hear the sound coming from where ever the rifle was fired, even if the bullet had already passed through the victim when the sound reached the hearer's ear.
If people heard shots from the grassy knoll, then that's exactly where the sounds came from, and misdirected analogies about planes passing overhead can't overcome that fact.