Secoinedchance, Charlton may list the *Z/Z at $9K, but who has any for sale at that price?...no one.
The note is super rare and is probably the only one on the market right now. Although you could argue the paper market is quite soft, and he probably won't get over book, but at one time they could have, and anyone looking to buy right now would have to pay the price.
It says right in the book, "only a guideline" which is true for any publication. I hate to see anyone miss an opportunity by going too strictly by the guide.
Example: I sold a coin one time for triple trend because I and the seller knew the trend was out to lunch...thought I was pretty smart...a year later the trend quadrupled...who's smarter now?