The leaderboard is based on how much time you spend IN THE ZONE. It's not as much about your average for the scored interval being green as it is the ability to keep your power (and cadence if it's part of the scored step) in the zone for the most time. The points are assigned based on the percentage of time you keep your gauge(s) in the zone. Here are the points and percentage breakdown.

Those windows are narrower than you think if you break it down. If it's a one-minute (60-second) interval, you can't slip for more than one second to get a 98% and the 5 points. You get an ill-tempered coach with a +/- 10watt window and you've got a barn burner on your hands.

The gamification and points are meant to keep it engaging and stoke the competitive spirit a little. Good luck and have fun!