There are many successful candidates with hours, myself included. I had 70 going in and did very well. Another guy in my screening had 300 and didn't do so well. Two people from the previous group had about 1000 each and did very well.
When it comes to the flight screening flying component they want to purely see your learning rate. You don't actually learn to fly in the traditional sense, the instructor merely shows you a maneuver and you repeat it, monkey see monkey do. But with each flight you should be getting better at the maneuvers and not making the same mistakes.
It's not all about flying either, the board and how you present yourself plays a very large part as well. Yes the flight component is important but your leadership ability and public speaking skills plus your interview performance all combine to give you your total score so don't simply focus on the flying aspect.