It's because the people you played were really 1600's self-rating themselves as "Expert" for their first 10 games. This means that if you beat them it counts as if you beat a normal 1600 so you only get 2 points. If you manage to lose to one, you would lose like 40 points because it counts as if you lost to a 1600. The expert self-rating starts you off at 1750 when you are 1600, but very likely those people lost several games and went below 1600 which is why it happened with a "1730" also (he is really 1580). When these people finish their 10 initial games, they will be at 1580 and realize that they've just wasted 10 games trying to play people much better than they are.
The point of this system BTW is that if you really are an expert who just came to Titans from normal AoM, you can quickly get up to at least 1700 since you gain 40-30 points per game. What really sucks though is that smurfs use it to play 1750's and then you lose 40 points for losing to one of them.
[This message has been edited by Matei (edited 02-12-2004 @ 12:13 PM).]