Also possible to be morphing toward the target-focused end of the spectrum, which can result in looking OVER your sights; you can still see them, and your brain tells you that you're using/looking through them, but your gun ends up lower than your LOS, and impacts end up consequently lower.
Concur that you need somebody in your face to see what specifically is going on; another set of eyes could pick up your eyes changing focus from sight to target and back, etc. It could be one of or a combo of any of what's been mentioned here.
Professional instruction is the best option but if it's not in the budget at the moment try having someone video you while you are firing. You may see yourself doing things that you don't realize you're doing.
Semper Gumby, Always Flexible
Do you dry fire? If yes, do you work both with and without a timer? If not, I would start doing that. As the others have said instruction, shooting more with a timer etc. All are good suggestions, but working draw, grip and trigger takes practice and unless you're shooting live rounds everyday I suggest that in addition to the other suggestions you start dry firing immediately.
First off, thanks for the couple of shout-outs from several guys, I really do appreciate it.
OP, there's really probably too much going on to give you any kind of simple fix via the forum - that doesn't mean that a simple fix won't do the trick, but diagnosis is really a dynamic activity which requires both the information from the target and the information from the shooter.
I can tell you that the first thing I'd be looking at is your grip. Then I'd be looking at how you manipulate the trigger during "slow fire".
Thanks to all of you for the responses and great advice. I knew I came to the right place to ask my question!
Okie John - my front sight is just a plain old steel blade that I have put a dot of orange paint to help with visibility.
Kimura - I do some dryfire at home, but I acknowledge, not enough! Sometimes I will work just drawing and presentation, sometimes I will work the same, but adding the timer.
Now, with the suggestions from all of you and some conscious thought, I think it is possible that my grip may be different when I am 'target' shooting and even dry firing vs. actual live fire with the timer. Not a different hold on the gun, but much more of a gorilla grip when I put myself under that stress. ....and it seems like I ought to pay closer attention to what I'm doing on the trigger as well!
Thanks again for all of your advice. I'm going to try paying a little more attention and making a few changes. I'm sure I'll be back!