It used to be as someone pointed out 150/half and 250/hour which is a discount for the hour, then it dropped to 120/200, now the norm is as you say 100/200. I guess the ladies just don't want to go below 200 but not all, you will see some fantastic English ladies offering 100/180 and an absolutely fantastic Scottish lady Alana offereing 100/150 if you book via pm..