So when I called them up to make an appointment, they told me the hour ground school is really just about 10 minutes, is there anything else that I should expect like that, is the flying time shorter too?
Did you ask them about flying time? Expect that the term "flying time" includes
at least from the moment the engine starts till when it shuts down. That means it may be 10-15 minutes from startup to takeoff and 5 minutes or more from landing till shutdown and you will get only 40-45 minutes of actual flying time. These rental companies need to find ways to save money. They may even include time walking to the plane or doing a preflight checkup as flying time. I know it sounds (and, in my opinion, is) unethical. But the way they see it, you're getting the flight for much cheaper than their regular customers and they have no duty to give you exactly what you pay for. BTW, my instructor refused to use his plane to give "Intro Flights" because he felt it wasn't right to his regular customers to charge one-time thrill-seekers so much less just for promotional purposes. I don't think this was great business practice either but he didn't really care since he had enough customers.