The ladies that visit San Francisco, unfortunatley, do indeed see many clients a day. 9-10 may be on the very high side, but I am sure that 7-9 per day is average. This is why they are always looking for that gent that will take them on a 4 hour dinner date in the evening.
For me, I try to schedule early in the am. I thought they usually started at 10:00am, but if you request a time, they go for it. Tried to schedule one recently, and the feedback indicated that they were available at 8:00am only. Great example of supply and demand in process. They supply beautiful ladies that give great service, and the demand keeps increasing.
The individual hourly rates in California are $300 US per hour.