Fair warning, this is advice from a newbie (I just proudly scored a 473 on an Aces Postal CMP competition...first scored match ever.), but I got this trick from a fella who can shoot a hell of a lot better than me (recently scored 370/400), and it works beautifully. I think it might solve a few people's issues in this thread.
I went back and reread the posts carefully and noticed something:
In contrast, with the 10M airgun (46M) I'm getting far less consistent results and more flyers wandering... one, and sometimes two rings outside the black. I can usually rope them in after a longer session with the pistols (final target or two may keep 9/10 in the black), but I find it more challenging and feel less confident than on the range with my .22's
Another poster stated that:
I seem to have the reverse happening. I can fairly consistently break 90 with my LP 10 at 10m but I rarely break 90 on a B8 at 25 yards with my .22 GSP. I'm still trying to figure out what is happening.
This may seem to not make sense. People are getting different results with the different guns. I don't think that this is a technique issue, I think that this is a "how you hold THAT gun" issue. Your basic technique is likely very sound, but your ability to successfully interface with the other gun is not for some reason. It can be reinforced and become a psychological issue with enough repetition. If that happens, you will have to create new shooting habits with the new pistol to achieve your desired accuracy.
Question: are you getting fatigued when firing with one gun and not the other? If so, you may not have found your horizontal natural point of aim with THAT pistol. Each pistol will have a slightly different NPA because they have different grips. Here's an extreme example of this: 1911 slab grips versus a Steyr LP10 grip. If you hold your arm in exactly the same place with both guns, one is going to suck to shoot with. The sights might align the same, but a different grip will give you a different hand position and gun angle. Pulling back to the wider picture, a different gun angle in your same shooting stance will result in a more uncomfortable shooting process that generates muscle fatigue as you use the gun in a way that strains your body. It also makes shots more inconsistent.
If you think this might be what's occuring, try placing a sheet of white paper on the wall and aiming straight at the sheet of paper with your IZH in your normal stance. Note its location. Then, close your eyes and lower the pistol. Without opening your eyes, slowly raise and lower the pistol again two or three times. Then open your eyes. If the sights have moved horizontally (don't worry so much about the vertical, that's controlled by sight picture), adjust your body in that direction. That is where your body naturally wants to point the gun. Go with it rather than against it. This will assist with the consistency, as your muscles will not work as hard to achieve the same results.
I hope that you score many tens! Keep up the fantastic work!