I wouldn't take eBay 'valuations' as gospel.
I was bidding on something and watched the price go up and up, then noticed that the other guy bidding had only bid on items from this one seller. I pulled out and the listing got cancelled just before it finished with the 'dummy' bidder in front because it was 'no longer available'.
Not saying it is like that in this case, but lots of interesting things going on out there.........
A DR400 sold a couple of weeks ago for $1200 and it needed a rebuild.
I listed mine that is pretty much ready to go and couldn't get more that $710.00. So it can stay in my shed for while longer.