For what it is worth, I've felt some pain & seen friends suffer same because we thought the above part was true. Even , and most frustratingly, when shooting slow bullseye shots I think the gun accuracy I measure on paper is sometimes a lot more about my trigger control & etc , even though it feels like I'm doing everything like I'm supposed to.
I'm back to trying to follow good advice (dry fire 100 rounds for each live fire round) & that seems to really help.
Not implying that that is what is going on with your testing, but for what it is worth that was what was going on with some of my recent testing. A clue to me was that my USPSA gun has something like a 2.5 lb trigger and that is the one I was least likely to shoot low left with. Trying to learn not to bother the gun until after I see the sights lift (and to routinely see the sights lift ) might be something worthwhile for me at least.
I encourage everyone that wants to take their shooting to the next level to read Jeff's post and let it sink in. It is human to want to cast our problems on anything or anyone but ourselves. Unless there is something mechanically wrong with a gun or barrel or sights that are stupidly off center or ammo that is WAY out of whack (as in running .355 bullets in .358 barrels, etc), any problems in accuracy at IDPA distances WILL be the fault of the shooter- period.
There's a reason Jeff knows this and I know this. Our pain, your gain, if you'll take it