20% is the norm here as well. I go to a regular salon and my stylist is a part time employee there. Typically I'm only getting a cut and eyebrow wax. Sometimes it's just bangs and a wax. But the service I get from this person is wonderful. As far as she is concerned, there is no one else in the shop but me at the time. Works for me.
I was going to another shop several years ago and the owner was the stylist. My cut was fitted in between other colorings, etc. Half the time my hair wasn't even completely dry when I walked out of the shop. Hence the reason I'm now going to another shop!