I have been wanting to explore this issue for a while.  Now that TER is back (at least for me),  it time to throw it out there.  It always galls me when I consider a girl who has rates that don't reflect multi-hour adjustments.  For example, if a girl asks 600 per hour that is her prerogative (for the first hour that is fine), but then if I discover she wants 1800 for three hours I just immediately drop her from consideration.  Sends all the wrong messages as to attitude. 1500 for three hours would be a fine accommodation. I am not really trying to drive the rate down to an unreasonable level.  The un-adjusted rate also doesn't make allowances for old guys like me who are going to use an extended date in a much less strenuous way.  I much prefer and patronize girls who are considerate in their rate structure.  Long boards rule.  

That's why there are more hookers than chemists.  Welcome to hooker math. I've seen where the multi-hour rate is HIGHER than the hourly rate.  

Also, rates may just reflect her own preferences. In some cases she is making her preferred-length session the most affordable. I know this isn't your example but you can find every sort of example you want. You're right to just move on if you don't like her rate card.

I'm not disputing your point. In fact, I agree that some older fellows would spend part of an extended stay in a relaxing recovery mode.  
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But another quirk is the well documented "Hooker Math".  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.

...and it's been brought up many a time.

I've seen more of those random walk rate structures than I can possibly remember.  I don't believe they are intentionally punishing longer sessions.  Therefore the explanation in innumeracy.

Depending on the industry the price schedule may or may not reflect some type of volume discount but is the hourly rate really one where we see that a lot?  

I've seen lawyers do the reverse, maybe either a free or reduced initial consultation.  Then billable hours to work on the case.  The goal is to drum up business.  So I think that is the key -- maximize income.
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Obviously an escort can't follow the lawyer method of a free or reduced initial session because a ton of guys would come in for a free 10 minute BJ.  Unlike a lawyer there is no follow-on work.
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What would help maximize an escorts income is what most (I would guess) are intending.  Sure some might want to limit session lengths for some reason, but I don't see that in most rate structures.  Since many guys can finish in an hour or so, to get them to stay longer and pay  more requires some incentives.
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If you hire a painter to paint a room, I bet he'd offer to do additional rooms at a discount.  So I do think it is common to entice additional engagement.

structure their rates to discourage 90 minute bookings, which works out exactly as your example shows.  The bookers figure if a guy can consider a 90 minute session, they will nudge him up to two hours by making that a more attractive option when considered on a per-hour rate basis as you have shown.  

you can tell who prefers longer visits by their rates. One exceptional provider I knew charged $400 for one hour but $800 for three hours. It was clear she liked longer sessions... maybe just from a convenience standpoint if nothing else (make one appointment per day and done).  

I have always found the girls who are most rigid with their public pricing are the ones who are softest about it BTS. Many do this intentionally, knowing full well when they receive a below listed offer, as many do, they have room to move.

about 15-18 indies a year on average, I like two-hour sessions, so I tend to steer  towards ladies that give a discount on the second hour.  I would only do three hours if I was one of the trimix users, and would probably go broke quickly.  

I've seen some who don't discount until hour 3, some not until hour 4, some not until their overnight rate.  
I technically start discounting at the 90min rate (my hr is 400, 90mins is 550, 2hr is 650 etc).
They have their reasons as do I....but one of them might not be bad attitude/GPS at all.  
Maybe one of them who chooses not do discount until beyond their 3hr rate will chime in.
Because rants (sorry "explorations") about rates/heaux math are always a riveting clam slapping good time.

with good incentives build in too encourage longer appointments.  No hooker math at YOUR business.  Kudos.  

Hour one requires an hour to get ready and a trip to and from an Incall  or the hotel fee
Not unreasonable to say with the above and screening three hours of work to the hour appointment.
Using that a 600 / hr rate is 200 per hour net. If charges second hour at 300 is making 100 more per hour.
The exception being if busy  could book another a half to an hour later  
Here is a rate structure that makes sense. Seems like the 90 might be too low but probably a way to get paid for running over the hour .
https://www.theeroticreview.com/reviews/victoria-sloan-176188

I think 90 min is that sweet spot for me. But I definitely have people I could spend 2 hours  or more with. I have my 10 year guru that sees me 2 hours sometimes 3 and we have been each other so long I just charge him a flat fee either way. I know he will be around when I need him so that makes it worth it to me. What really ticks me off is those who try to low ball but them ask for multiple hours afterwards. It just leaves a bad taste.

Did it ever occur to you it's up to HER what she charges for how long, why and with whom?  

I agree I think alot of providers structure rates to accommodate what kind of experience/ date they prefer to have more of.  

But I think most guys here will agree that a hundred dollar "discount" on a four hour date isn't really much of a "taper" Especially when it works out to EXACTLY twice your two hour rate. There is ZERO cost savings per hour in booking a four hour date. That's NOT a taper in my book.

You're almost thing maybe it was a typo. The 3 hour rate has a $50 discount from twice the 90 minute rate. Might have expected something like another $50 off for the 4 hour -- maybe 1400, or at least 1450 -- but again it might be intentional.

that can afford four hours are 70 years old and want 3-4 pops.  She KNOWS she'll be working her ass off.  Lol

Most guys are going to look at this and be incentivized to book 2 x 2-hour appointments.  Most John's are not rocket scientists either.  They are just going to say I could come 3 times in two hours or we can chit chat more and I can come 3 times in 4 hours.  Hmm.  I can schedule 1 x 4-hour appointment and come 3 times or I can schedule 2 x 2-hour appointments and come 6 times or twice as much for the same price.  No brainier for most guys.  

It probably won't work on the same day.  Lol

I can see booking two hours in the morning and then another two hours later in the day.  

Translation: Lady isn't going to let a guy come 2 times in 1 hour.  Hmm ... If you want to come twice then you are going to have to at least book my 90 minute session - I am gonna make you pay for it.  I can chit chat enough to ensure that the guy won't come 3 times in 2 hours.  If you want to come 3 times, then you gotta book my 3 hour session.  The third one is always a pain the ass and requires more work than the other two so I gotta make you pay for it.  I am not super hot so I know you are not going to come super quick.  That said, sucks for the guy who comes within the first 10-15 minutes of a 1 hr session.

for other guys, I could use two hours twice in the same day.  Not sure I could do the second two hours justice, but if you're buying, it doesn't really matter.   Thank you in advance for your generosity.  Lol

and look for ladies whose rate structure suggests she prefers longer appointments as well.

Can we connect the dots here?? wait for it.....wait for it......lol

Get the impression that one might take the 10 20s over the 6 50s. After all, the additional 4

I tried to find it on You Tube, but in vain.   However here's a short clip that will give you an idea of her humor and make you smile.

but I just cancelled on her so I can stay home and make a pot roast.

and apparently cannot even really copy them well.

WOW!!!that was uncalled for!

over something he said two months ago?  Lol

A VERY slow burn I guess