10x is probably way too low a magnification level to really see the results of your work. I read an article a while back by noted audio guru Tim de Paravicini about his vision of further technical advances in stylus design that will continue to harvest ever more of the complex waveforms that are embedded in vinyl. One of his points is that we still are only sensing a fraction of the information contained in the vinyl with current retrieval techniques, and that even old records actually have captured modulations at the nano-level that will some day be able to reveal the vast amount of information that is currently dormant in all our records.
If Tim de is right, we will one day have cartridges that scan and detect groove modulations as small as 1/millionth of an inch. You may need a bigger magnifier to see if ultrasonic waves are really harmless to the full waveform, or if it may actually be making your records useless when that great day comes. I will err on the side of caution and not risk my records until someone does a study using the same kinds of instruments that de Paravicini refers to.
When or if ultrasonic cleaning gets a clean bill of health in a scientific study, I will continue to use my Nitty Gritty.
If challenged, I will dig up a URL for the article I humbly attempt to reference here. Tim is regarded by many as the Einstein of audio engineering, and his own products have been superb. It's too late now, but I think I will probably want to reread it again.