The weekly rotation is the norm with Chinese shops. It works well for both punters and house.
Change day is usually Monday.
The girl in the advert is not who you will see, it is B & S but that's the way it is.
Every Chinese shop has an Uncle or Auntie, they are not a minder or enforcer, their job is to cook the meals, clean the place, get the shopping and shuffle the punters about if their is a waiting queue.
Getting to know Uncle or Auntie is a smart move, even the occassional tip if it has been earnt.
I have known them to text 'favourite' punters with detailed and accurate details of the girl, but I've also known them to lie.
The 'rotation' as some places may well be planned well in advance, especially for a good girl or a girl who likes a particular shop. Auntie or Uncle liking you may give you a look at the rota.
My experience is that few of the girls are trafficked or working under duress. They travel from shop to shop/location to location unaccompanied at their own expense.
I don't ignore the fact that the Boss may have some other hold over a girl and that means she can't stop working but I've only once encountered anything that caused me to doubt.
Hope this helps you.