For a 37' boat, that sounds about right. And I agree, and type of pressure washing can be bad if the yard doesn't know what they're doing. Sanding is the safest way, but more labor intensive.
I'd also ask for a breakdown of what each step costs, so if you want to change a step, like materials, or a chemical peel instead of sanding, then it's easy to see the changes in price.
Merit 25 # 764 "Audrey"