as a general practice. I just read an article at
In general, insurance companies are required to give you the cost of replacing your vehicle. While laws vary locally, this is the $ you have to pay to find the same vehicle at a dealer - without negotiation. They can't claim subjectively that you will be able to negotiate for a lower price. In some states, they are legally required to pay you the sales tax and even the registration fees. But, don't expect them to offer - you usually have to firmly demand it.
Fact: Insurance companies try to minimize any payouts. They don't like you much aside from the fact that you send them money. When you want some back, they will try to screw you. The even hold monies owed you, if even just for a few days, so they can keep it invested longer.
So, use an appraiser, call local dealers yourself. Get what you are entitled to.