My dyno guy doesn't tune the bike, he just runs it on the dyno. He might make recommendations about what to do with jets, needles, etc. according to the dyno results, but he then goes off and does something else while I do the jetting changes. When I'm done he comes back and gives it another run. I like doing it that way because I know exactly what's been done, and I save a bit of money by not paying him to be spannering on the bike.
He doesn't do it that way for everyone, only old farts like me who like to have a hands-on involvement. Some people don't wanna get their hands dirty. They just leave their bike with him and come back later to pick it up when it's done.