Fairness aside, it might make more business sense too. The price of a good or service is what someone is willing to pay for it, but another important question would be "how often will they pay for it?". My feeling is that by drastically lowering the price of sessions, thus undercutting virtually all the competition, you greatly lower the barrier of entry for potential customers. For example, you might spend $200 a year on ice cream cones that sell for $5 each (40 cones per yr), but if that same ice cream cone were $200 each, I guarantee you wouldn't buy 1 of them a year, you would never buy one at all.
Similarly for sessions, if someone tried lowering them to $100-$200 each, I'm tempted to think that a girl could do as many a day as she wanted, and possibly make more money than she would have charging $400, but only doing a couple sessions a week.
At the very minimum, it would be interesting for someone to try it out for a month by running a "half-off special" and seeing what kind of increase in business they get.