The guy seemed friendly enough, and was concerned enough
(in me as a possible/future customer?) in my question to enlighten me of this practice, but I don't quite understand who is keeping track of sales of this item: the seller, or eBay???
I don't see why eBay would care...And if it's the seller keeping track by use of eBay's records system, he's way more skilled than me in using the eBay history to keep track of any particular item...
Seems like a risky way to keep track of sales/inventory in either case...
I'm not a businessman...There must be more to this tracking business than I follow...