I have met some girls put a price and then quoted as everything included and when you meet face to face they give different quote by asking extras.It is a trap to attract customers.They waste our time as well.One day I went to see a girl. she has photoshopped and not worth paying extras she was asking.I told her I am not prepared to to pay extra everything must be included.She refused and I walked away,
What a cockwomble! What you describe above, SP's adding extras once you arrive is wrong and if it happens to me I walk, but it's only happened twice, you seem to find it a common occurrence, no doubt due to piss poor communication on your part, and the type of escort you are booking. It sounds like you make a point of trying to find the SP's in your area that are the most desparate, most likely to not be doing their own comms, and therefore are the most likely to be controlled by someone else, maybe not particularly happy to be doing the job.
However none of that excuses your boundary pushing, creepy af, haggling ways. In fact it makes them worse in my opinion.
In almost every other aspect of my life, I love a bargain, I'll stock up on things when they are on offer, I'll maybe not buy them if they are not. I hate people who brag about how much they spent on something, I'm far more likely to boast how little I paid. But in this part of my life, never haggle, make sure the SP knows before you go what services you want, so she can make you aware of any extras. If she hasn't and tries to charge them, simply walk. How enthusiastic can you expect an escort to be when you've just told her that you think she is worth less than she charges