I got the following reply this afternoon from ST on the subject of adding additional users -
Hey Bob,
So, you might have noticed that we’ve temporarily disabled the ability to add or remove users from your account… don’t worry, it’s a feature!
We’re improving how user sharing works at the moment - so rather than have new people go through all the inviting and creating only to find out that they can’t actually share the account just yet, we decided to disable it.
Not to worry though, it’ll be back and better than ever, soon! Sit tight, and we’ll let you know when you may add (and axe) loved ones and friends alike. Sorry for the inconvenience. I’ll be sure to let you know as soon as we turn this feature back on.
If there’s anything we can help you with in the meantime, don’t hesitate to ask!