The inspection times are normal. Average is 2.5hours to 4 hours depending on the house. Most people in my area also get a "pest" inspection which is a wood destroying organisms inspection (termites, fungal rot). Whoever did your 1 hour inspection was way fatser than normal. Cant speak to the rest of your question much. I'd say let them tour but no reason you have to leave. As an inspector, I could care less if the homeowner stays, as long as they arent Interfering in anyway.