From your post it looks like that there might be violations of Retail License terms for Microsoft 2010. It appears that you have more than three installations of Office 2010 with the same license, which is strictly prohibited by Office EULA (Yes, there is a clause for portable devices for the same owner, but it makes it up to two installations of Office 2010 max!)
I could be wrong if you have purchased your Office 2010 for an organization via Volume Licensing Program. But in this case you are not eligible for that Office offer
Please clarify what edition and number of licences, and number of installations you would like to upgrade.
Difference between subscription and a program is that you can use subscription on up to 5 PCs or Macs
shared among all users in the home for duration
of that subscription. And commercial licence for an Office 2013 is a life time, but to install and run one
copy on one computer
only. Looks like even transfers are prohibited.
And for sure
Quote: Originally Posted by Microsoft Office 2010 EULA
After you upgrade or convert, you may no longer use the software you upgraded or converted from.