It sounds to me like he has a pricing structure that is fine for expensive cars and owners that are happy to spend a lot of money, but it's not attracting people with 'lesser' cars. He can't have one price for one type of car and a different one for another. Charging less for 'lesser' cars will mean that he'll have to charge less for expensive cars too, as he's devalued the product/service.
With that in mind, he could end up attracting more business, but not earning any more money. I was once told by someone that does a similar job to me was that he'd doubled his prices, and as a result of that, only won half as much work as he used to get. Sounds like a plan to me.