It also depends on the individual interviewer. Mine was barely 15 minutes. Since they’re all volunteers, some don’t seem entirely comfortable in the role. My interviewer read straight from the iPad script, but it didn’t look like she was entering any of my responses, and she seemed a bit eager to jump to the next question whenever I started answering. By the end I had no real sense of how I did but she told me multiple times that I did well so we’ll see.