I see nothing to suggest that this offer is suspect. The lathes are being sold by Myford in it's latest incarnation – spares, support and refurbishment rather than manufacture. The business details – phone numbers, address, etc all match an established business, which can be visited if necessary.
I'd have thought it quite likely that a firm specialising in Myford stuff would earn money by buying up and refurbishing second-hand lathes. As a business they're are better placed than individuals to buy in batches – when a University or similar closes a training facility and puts 10 on the market. They're also well placed to fix random lathes picked up in poor condition – at trade cost they have all the necessary equipment, skills and spares available.
Given that Myford kit attracts premium prices, this is probably a reasonable offer. If the previous owner ruined the bearings with 20 years of grease-gun abuse, Myford will have mended it. Buying direct from the previous owner means you own the risk that the machine might need expensive repairs. The ebay offer appeals to people wanting a Myford who are nervous about buying second-hand.
The prices seem fairly typical. That the number on sale varies doesn't surprise me much. We don't know how fast they're selling or how fast Myford can restock. Possibly Myford have several sat in a repair pipeline with more candidates awaiting inspection in a shed. Plus a man out trying to find more.
Dave