We’re talking about goods bought, not about where it’s charged. Also you can buy plex on one account but that doesn’t mean it’s thus limited to that account: you can trade it, transfer it and contract it. So if it can be done with that it could be done with other stuff, unless specifically stated and ESPECIALLY for items like these.
It’s also stated (somewhat but not enough imo) on the main MCT store page so that infers that they know it’s a potential issue (only took them a bit) but NOT on this sale page, which is the page people use as it’s… a sale.
Just sayin.