I share a slightly different perspective on the matter. I've adjusted my M2 rangefinder a number of times (when I owned it) and my M6TTL a couple. I may be a little braver or just stupider than the "get a CLA" folks, but it's not rocket science -make a slight turn on #1 in your diagram with the proper tool, slap the lens back on and see if it aligns. If it does, you won. If it's further out, you turned it the wrong way. You just need to understand that these are precision parts and not a lug nut on the wheel of your car, so be gentle.
On a second perspective, if you're talking about "slight" misalignment and that "The problems doesnt seem to interfere with focus at all", than what's the issue? I mean, precision focusing at 1m might warrant the repair, but if you're shooting f5.6-22 and mostly shooting things 5 feet away more more, than is it so hard to live with it? This is also coming from a guy who has had the vertical alignment off in his M6TTL for about 2 years, so I tend to be biased on the matter.
I have had rangefinders knocked our of alignment from falls, rewind knobs break internally, meters go faulty, holes in my curtains, and probably a bunch of other things. I bought the tools and was able to fix them all myself and all my friends and family can attest that I am no genius. There's many things I won't even attempt to fix in a Leica, but I guarantee you that if you send it to Youxin Ye and ask him to videotape him doing the alignment, it would be the exact same thing you would do anyway -hence why it's a $20-40 job.
