@musteni Glad you thought it was useful. :)
I did forget to add that the only reason I even run the restaurants for a while is so that my Sims can have excellent quality meals when dining out - not for profit. So I never go above the 125% mark-up, which also contributes to the rating. So for me success is not wealth but a well-functioning, highly rated restaurant with fully trained staff.
But I do have fun while managing the restaurant. I used to work as a waitress many years ago and I can honestly say that the game emulates the hustle and bustle of a busy eatery quite well.