What if the same patron asks a lot of questions?

This really is a matter of professional judgement.  The definition of reference counts reference transactions, not questions, per se.  If a series of questions are related to one topic and help produce an in-depth answer, for instance cancer diagnosis and treatment, I would count them as one transaction.  In contrast, if a patron asked about information on baseball rules, and then asked for a recommendation for a good mystery author, that would clearly be two transactions.