Yes, LAST sounds different, as I said, it has less grove noise. Good, bad? I dunno, really don't care. It won't stop me from buying an a used LP, but I won't buy the treatment either.
David, the problem with "really dirty" LP's typically isn't that you haven't got it clean, it's that the sounds you're probably still hearing are from cavities in the vinyl - not bumps of dust. The cleaners can't help with that sadly. That's why even a good cleaning that sounds a lot better will still have some noises.
Maybe that too but for the most part the fungus, dirt, whatever is still there even after 4-5 cycles.
david