When my wife's van was 'totaled' after she was rear ended, the insurance company told me it was because they had to price the repairs based on new parts. They said if they were allowed to use used parts they would be able to keep a lot more cars from being totaled. This is in Oregon, I know laws vary by state.
We 'bought' the van back from them, pocketed the $1100 (13 year old vehicle at the time) and my wife continued to drive it. We just can't open the rear door.
Don't you just love this government supported scam we call insurance?
Good Luck,
Dan