With Erie I increased my deductible to $1,000 which saved quite a lot. The savings over a short time makes up the difference.
After the change, I got in a fender bender.
The insurance adjuster gave a high estimate so I got a check. I fixed my car myself, didn't cost much and you really can't tell any damage. In other words it boils down to the agent, insurance co., etc. In the end that's what matters most. So 80% of book value could possibly be more that 100% of another's valuation. My 2 cents.