Definitely impossible to change difficulty of an underway campaign?

[jameson]

You won't like this, but I'm fairly sure that if you uninstall the game it will leave your career settings, skins and various other bits in the il2 game folder. If you have space on your harddrive you could copy your current game elsewhere and try it!
Otherwise, if you have another computer, you could install 4.07 from the dvd, play 2 or 3 missions of a campaign then uninstall and see what's left, to confirm this idea. A long shot, but maybe your only solution, if it works you could reinstall into the original folder and patch up to where you were.
Interestingly I've been playing the stock 109 campaign, (Army Group Centre), in 4.07 and the same missions in 4.10.1 and they aren't the same, similar kind of thing but completely different targets and locations on the same Lvov map. I have no explanation for this. Hope this idea helps.