Geoffrey, on a "person account" our service assumes the contact that has been combined with the account is the selected contact.  That is why we do not show the contact selection.  Both account tags and contact tags will work as expected in the document.

What if there is more than one attached contact to the account? How can we differentiate between the two or three?

Geoffrey, could you provide a screenshot of what your person account looks like?  Have you created a custom relationship to other contacts?