I have had a couple of horns now that I thought were "super clean" by me and still had some issues.
Ivan's attention to detail actually got them clean and playing better. I think over time self cleaning will not be able to remove all ills, no matter how hard you try.
I have not experienced any issues with problems as a result of cleaning, but then again I've only gone to Ivan, and reading some of the horror stories, I shan't be going anywhere else anytime soon!
The moral of the story is....find a damn good tech, and keep 'em!