My 2 cents...you aim on the fly. You rarely look at the shot or the position and adjust after you're down. Pool is a static game, and there aren't any moving parts to watch. You're playing like there are moving targets. A short pre-shot routine may give your eyes/brain just enough time to make a better alignment for each shot.
You come in from different angles on each shot. You switch your aiming eyes/alignment because your head is in a different position as you get down. You play really good, then miss an easy shot. Your eyes are adjusting on the move. Your brain is adjusting on the move.
Take a second and look at the shot consistently. Give your body a chance to get on the correct shot line. You switched where your cue was located under your eyes a couple of times. You missed badly when you did. I know. I do this from time to time, too.
Best,
Mike