There’s new wording added to the February 2016 Product Terms that allows EA customers to reattach SA to licenses. Yes, really!
If the customer transitioned to an Online Service or purchased a From SA USL instead of renewing their SA, then they can reattach SA to a license at anniversary or renewal without purchasing a new license. They need to order SA for the remainder of the enrolment term, and of course they can’t buy SA for more licenses than they had originally.
Read the full terms on page 72 of the February 2016 Product Terms.