Standardized tipping in this business does nothing but drive already high prices , higher.
There is a lot of competition now and you should be able to get a very, very good service for $100 or less- total .
I think it is time for prices to come down, given the competitive pressures.
Places like Temptations/Ambrosia have a pricing structure that forces the ladies to press for bigger tips. Stay away, unless you are getting a particularly unique and enjoyable service.
Tips should only happen , in this business, when, after the fact, you feel that you received a really great service, well above your expectations.
Sexual urgency drives a lot of guys to spend way too much for way too little. This does nothing but push the costs up for everybody. Unfortunately there are a lot of ladies who are prepared to take advantage of the foolish. "A fool and his money ........"
Fortunately there are a lot of fine ladies who don't.
Repeat with the ones you enjoy, and give them a bottle of wine on your favorite holiday.