The distribution of points is independent of how many people are on that list. The 1st, 2nd, 3rd, etc etc...positions in the list are always going to get the same % of points awarded from the total available. For example if I'm in the first position I'm going to get say, 15%. If there are two people on the list, and I'm in the first position I'm going to get 15%, and the next person is going to get 12%. The available pool is also not being subtracted from when those points are awarded.Here is an explanation of the method of distribution, but the key part is quoted below:
If I am interpreting this correctly, the points pool is being divided up among the players on the top attacker list, which is to say that if two people are fighting one monster, they aren't going to get as many points as they would if they were fighting the monster alone.