Blue book or auction prices are only a guideline. The condition of the machine can influence the price up and down a lot.
A year ago, I was looking for either a 950 or 966C. Prices varied from about $15,000 to $50,000. A $15,000 966 needed fifty thousand or more in work. A $28,000 950 also needed a lot of work. I was going to go ahead with that 950 and do the repairs, but someone else beat me to it. Thank you to that buyer!! Before long, I found a 966C in much better condition and bought it.
My conclusion is that one is far better off paying more for a machine in good condition than paying less for a worn out machine. Before long, the more expensive machine may cost less.