I suggest to give less points to 2 player games (maybe half of what you get now).
2 major reasons for that:
1.) They are highly infected by the luck of the begining situation.
2.) They are quickies which don't take long and keep you under preasure
Example:
I lost today a classic map freestyle game against a cook (I think I'm a sergant 1st class - 2 stripes and a diamond). The game started today and was decided more or less by luck (pc hang up in important situation) and it cost me 45 points. I won yesterday a world 2.1 standard 6 players game which lasted 2 month. And I gained 99 points. Where is the relation?