I'm going to attempt to improve on what Achiles has written but I'm not entirely sure I understand it myself. Let's give it a go.
The points gained or lost in a game depend on the players in the game. Points gained or lost come from a common pool and they are calculated before the game starts. Basically each player adds 1% of his or her points to that pool, but this is not like poker, it is not as if you were betting 1% of your points; bear with me.
Say that player A has 400 points, player B 100 and player C 50 points. Player A makes the pool go up to 4 points, player B adds 1 extra point and player C 0.5 points. The total number of points that can be gained or lost in this hypothetical game is 5.5. Still with me? Good!
The game ends and it so happens that player A and B are tied for victory. The side of the winners is comprised in this case by player A and player B and they get a total of 5.5 points for their victory to divide among them. Player B has less ranking points so he or she gets the share of the lion. Poor player C is the only one in the losing side so 5.5 points to be lost among the losers leaves player C to lose 5.5 points all by him or herself. If there were more losers those 5.5 points would be divided among them. The player with the most points would lose the most points as well.
Hope it's clearer now. The moral of the story is: don't let people tie in a game with only 3 players because if you lose you lose it all as you have no-one to share your loss with.
------------------------------------------------------------------------------
Towards World Domination!
(but never quite reaching it)