Difference of service level by shop is hard to tell bro. I've met the same girl at different shops and the service level was the same, but big grain of salt here... My definition of "service" is different from most bros here. I rate what the girl lets me do to them much more than what they do to me. Like, if I meet a girl and she just lies there but lets me do more to her body, that's top class service to me. But if I get another girl who licks and sucks like a champ but doesn't allow a lot of things like DATY, that's bad service in my book. Bros who like to lie back and be served like a king will love the second girl, not me. And they would probably call the first girl a "starfish".
Anyway, cut a long story short, I reckon service level is always down to the girl, not the shop. Where the shop makes a difference is how long they keep the girl in the shop, based on their expected level of service. Example, Ginza might have certain service levels. They hire a new girl thinking she does the service they expected. After maybe a week or 2, they get feedback about the girl. If she's not up to par, they get rid of her.
Hope that makes sense!