STN's prices can change, so their listed sell price being 16 at the time of this suggestion being made - when they no longer own one - isn't a guarantee that the sale was for 16 Keys. You'd need concrete evidence to confirm the sale is 16 Keys, so without that, the 16 Key sale here isn't usable.

That said, there was a new sale for 16 Keys. It's now listed for 21, so 25 may end up being high, but there's not enough at the moment to exclude it.

https://imgur.com/a/vZlM4sY - New sale for 16

https://imgur.com/a/oS4xYio - Listing for 21