First: payment comes after the services, so, it is to your discretion... you are complaining about something you decided to do... though at 5k are you including payment for special services rendered as a tip?
Second: you have often displayed a bit of a nasty attitude in your comments here... if that attitude goes along with your tips, you will not be appreciated...
You have mentioned wanting to be 80 yrs old and going with teenage girls... I am sure they will charge accordingly if you can find one.
Be it in a tourist area or not - I smile easily, I can speak Thai, I understand the culture, and I tend to be a decent tipper out of a sense of sharing, not obligation...
You are even angry and resentful of your own chosen actions... anger doesn't usually go over too well here... chill out and try and enjoy your vacation w/o being an angry guy..