Just joined up. I go by the same handle on WUS. So I was just researching the Grand Seiko SBGX115, because I own one, and I like to track it’s value now and then. After clicking on a few datapoints, I found myself looking at the very same watch that I now own (same seller and pix as the WUS ad), except WatchCharts lists it as having sold for $445 more than I paid for it, which is about a 25% margin of error.
As the site seems to track prices by crawling forum data, this is not surprising to me, because lots of times the final selling price is not posted.