Hi,
Regardless of the buy/sell price issue..... two other factors affect why valuations are a contentious issue.
The first, insurance valuations, which are, imho, an area which, in my opinion has encouraged fraud, as they seem often to be three/four times the going market rate (and so drive up premiums for the prudent).
The second, many people do not carry public liability insurance, me included, and are not prepared to be sued, simply because their estimation was not met in the market-place.
I am neither an actuary (risk assessor) nor a clairvoyant.
Regards,
Marcus