Great advice. I’d think even better would be one question. Three is OK, and better if they are follow-ons to the ONE question.
You’re example are great — my burning question (because I only may get your attention for five minutes — which may be worth thousands of dollars) should be focused, to the point and not really ask for anything else.
It’s the idea of “if you were next to Tony Robbins (1) waiting for an elevator and then in the elevator, what would you ask him” — it works for any person. One question, one answer.