Thanks for the clarification Tony.
All races are supposed to hit the target time. When you want two laps, you have a longer beat (and run). When you want three laps, you move the weather mark closer to the gate.
Either way, even if you run five laps, you need to hit the target. (Of course, no one would do that, because the laps would be so short that the carnage at the marks would be incredible, since the boats won't have time to separate.)
Personally, I prefer three laps as a sailor, because it keeps the fleet closer together and allows for more tactical work at the marks. Other sailors prefer two lap races because they tend to be more strategic. Good RCs run a mix.
Mike