3 is the center number point. In this case, winning against someone directly above of you grants you 4 points, and winning against someone directly below grants you 2. Meaning if you win against someone 3 spots below you, you will get +0. This includes when you are challenged, meaning the top clan can still gain points.
And also, if you lose against someone directly above of you, you lose -2 points. Meaning, you cannot lose points to someone 3 spots ahead of you. You lose -4 points if you lose against someone directly below you, etc etc.
Except that points be cannot won or lost more than 7.
If anyone can think of a better one, we'll consider it.