I was with Heacock and am now at the Barrett-Jackson endorsed insurance. The actual insurance is Chartis and had no problem getting signed up with them for agreed value coverage.
When I switched from Heacock to Chartis, my rates went down and my coverage went up. I have not had any claims with either -- so far they've just taken my money; so I have no idea how things will go when and if that time comes....
I'd just check around with companies that are worth going with and seeing what you can get for coverage and rates.
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