PS: "Unless the subscription is an OEM equivalent of 365 Personal" Why do you say the subscription is not OEM the same as other versions of Office and other software? The computer manufacturer will
have paid Microsoft for the the licence as they do for Microsoft's other products, including Windows.
Logically, this "free" Office is an OEM license. BUT, it has been identified as 365 Personal. I have not seen any mention anywhere that there now is an "OEM" class Office 365 Personal license. There could be, there logically should be, but I have seen no
proof of it. There is no mention of an OEM type Office 365 Personal license with any specific limitation on who can/must activate it in the current 365 MS License Terms document. There were specific license terms for OEM Office 2010
.
Yes the manufactures have to buy these licenses from MS.
Yes, I expect they will pay significantly less than US$70 retail price.
Back when 2010 Starter was the "free Office offer" I found some MS documentation that confirmed the manufacturer cost as $1 or $5 for each license.