Lady had an ad on another site. Her pricing is baffling.
30 minutes.  600
1 hour.           700
1.5 hour.        1200
2 hour.            2000

So many SWs are quoting $500, or more, for an hour and their "no" list contains everything except a grab of a tit! For $500, I expect as much foreplay as I want and GFE.

I used to think there are a lot of providers that don't have math skills on their menu, but after seeing a few hundred indies over the years, I can tell now that she prefers one-hour appointments.  She is encouraging you to book one hour and discouraging you from booking less or more than that through her pricing scheme. There is a method to the seeming madness.

Why not book 2 consecutive 1 hour appointments? L9l

One hour on, go have a nice dinner,  then return an hour or two later.  

There are plenty of even weirder price schedules that ARE real Hooker Math:  
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http://www.theeroticreview.com/discussion-boards/ter-general-board-12/hooker-math-966138
Basically, it's non-linear, non-monotonic function of time. That would be something like:
1 hr 500 (500 per hour)
1.5 hr 800 (533 per hour)
2 hr 900 (450 per hour)
3 hr 1450 (483 per hour)
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Go figure. Literally.  
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lester_prairie called it a random walk.

It's called assymetric dominance effect, or more commonly, "decoy effect" as per laymens terms.  

When I see these kinds of rates, it is just an indication that the provider has identified the timeframe that works best for her and sets her rates accordingly.  As long as it isn't a mistake, I don't understand why this is an issue and besides, a simple discussion after your initial meeting (and finding each other mutually acceptable) might result in a more favorable future rate.  At least that has been my experience.

I think that assumes too much planning on their part.  More likely, in my opinion, is that they just think "how much do I want for this time, how much for that" without doing the math to see if there is any consistency or pattern.