I think it seems fair considering the circumstances. Chuckster explained the time may not be the 30 minutes you account for. There is the opportunity cost as well where he could have spent the hour giving someone else a lesson and making HK$500-700. The risk to the vehicle for an unlicensed driver (remember the instructor isn't there to stop you making mistakes, the examiner waits for your mistakes to happen then fails you). Your lack of options since you don't have a license.
If you take away these costs, then he's probably only making a few hundred on this. instead of getting annoyed with it, you should focus on the test, using the car you are familiar with, rather than risk failing and having to pay another $2,000...