I thought I'd offer some advice as I am a Total Loss Adjuster for a major auto insurance adjuster. (Don't Shoot!!)
Yea, the way that they derive value is not based on NADA, Edmunds, or Kelly BB at all. Most companies (that I know of) use a company call CCC to produse a report on fair market values for that vehicle. CCC is an nation-wide independant 'surveyour' of sorts, that scans advertisements and actual vehicles and records the 'take' price reported by the seller (be it dealer or private party) in ALL market areas in the US. Then the values are slightly adjusted to allow for mileage and feature differences. I can explain in greater depth, but if this is what they use, it is actually extremely accurate. You can also request a copy of the report, or just the valueation number which you can use (along with your insurance claim number) to view your specific report online. I can explain this in greater detail if you all would like, but I'll keep this kinda short for now
If you are using NADA, KBB, and Edmunds as references, then be sure to use the PRIVATE PARTY values, not the 'retail' values listed. If you try to negotiate with the retail values, the adjuster will pay no attention to them. You would have better luck finding similar vehicles in a Truck Trader (within 100 miles unless you live in ID or Montana ) and sending those to your agent. An by similar I mean with REALLY similar features and mileage. Mileage is key, even on vehicles that do well with high mileage like a cruiser.
I know with my employer, we really don't try to low ball anyone; we just offer what similar vehicles are selling for in the area. The problem is that vehicles like the Cruiser are a 'niche' vehicle and are collectible, which inflates what we pay for a 'good vehicle' compared to what the market value is on what most people sell them for.