It's their business. They juggle, and even if they like you, they'll juggle you, too. Ever been around one when she's on the phone with a guy who thinks (or hopes) she stopped working, because he sends money, is a boyfriend, is married, or all three? And if she likes you, she won't want you to know how clever she is. When she calls and says she'll be two hours late because she's copying notes at school from an amiga's book, she's really boffing some dude and getting cream all over her face. And should you call midway into her session and she happens to answer, she'll put her finger over her lips to the guy she's with, so he remains silent. That's just like she does with you when her "boyfriend" is on the phone, and she's prancing around your apartment in a bikini.
They have to make a living, and you're not a meal ticket. The only question is how to deal with it. If she's extraordinary, you might wait the two hours while she "copies notes" from her friend, especially if she's going to stay overnight and not charge you. It's a balancing act. I think if it's a girl you have a quasi friendship with, you have to cancel her ass once in a while, or not call for a few days, too. It can't be a one-way street. Yes, she has to juggle to make money, but your time is valuable, plus you have pride. There's a lot of beautiful girls who'll suck your dick. Show her their photos.
In many ways, the psychology involved in having a relationship (of sorts) with a working girl - by that, I mean she would rather hang with you and make less - is much like it is with a civilian girl. You can allow her to abuse you a little because she really is hot shit (never her let her know that), but you can't be afraid to blow her off, too. If you are, she'll smell it like a cat smells fish.
In fairness, many hot girls like to have guys they feel are friends, and they're sincere to a point. It's lonely for many girls, especially those who are living far from family and friends. Girls at the work places are colleagues only, and most guys are clients. So she may really like hanging, going to the beach, a movie, or even to your apartment. Sex may or may not be on the menu, but she's not counting on big money from you. She'll weigh the totality of the relationship and decide when and if to poke you, and you'll be happy when she does. But you'd better be happy the other times, too, or she'll smell that shit, too. You really better be a friend if you want to continue with the half-price shit.
But that gets back to can you tolerate the lies she executes with near precision, day after day. She wants you to believe she's on the way out of the biz and she may be. If she really sees you as a friend she may tell you she really doesn't like to work anymore, and that may be truthful. But she still is working, make no mistake, genius boy. She wants you to see her as a non-working girl (you made it clear you don't want to be regarded as a client), and not think she likes being a programer.
Maybe you can tell her to be truthful when she's working. Most girls, however, don't want you to know if they have feelings for you (even small feelings). They want you to think better of them. And besides, do you really want her to tell you? Not unless you're her pimp.
Mix it up. Go to an MP, terma, until you're feeling the need for a little more substance with your favorita....
....
little being the operative word.
Jazz Musician