It's my understanding they're under Hasbro's umbrella but basically wholly separate entities (possibly even sub-contracted to another company entirely?)I think that is entirely possible because my mother ordered some things from HTS for Christmas gifts and when it arrived the packingslip was from someone's WalMart order for pillows (or something like that).
I'm 99% sure they don't fulfill their own orders, which is not uncommon. The arrangement usually works that HTS owns the inventory and manages the stocking levels, but the stock sits in a shipping hub managed by a third party who actually does the shipping (sometimes managed by UPS or FedEx themselves).
My last several shipments have come from a bunch of locations in Pennsylvania, Ohio, and West Virginia. I think that is why you see your order split sometimes, its actually being fulfilled from different warehouse locations.
Hopefully they at least manage their own inventory, and hopefully once in a while the product managers for the SW line get reports on how well or poorly things sell.