I moved a Madison back when I was operating out of TN. Real estate lady that sold some folks house bought the table from them and it was in near pristine condition. I know she had the table appraised for insurance purposes and IIRC it was something like $12K however it's been my experience that sale value is a function of availability, condition, level of table detail and what a buyer is willing to pay.
There's 2 Klings on ebay now - one for $19K and one for $29K. Also an Arcade for $5K. IMO the Kling is just an Arcade with more Korbels so it makes me wonder why there is such a difference in asking price. When you look at all the other antique tables for sale it makes you wonder how they came up with pricing since I'm not familiar with any blue book of table values.