Does GT score you with Kills or Flag Scores? Kills can be up to 50....but Score is onle 2 or 3.

Halo reports the "score" but if this is not equal to Flag scores ingame, Halo may be actually be reporting kills. Some games combine kills, objective points, etc into a single main score for the player, so it is possible it is a combination of both.

I would recommend contacting a Halo fansite to determine how score works for the game. Otherwise, an easy solution would be to play on the server and compare your ingame scoreboard to that on GameTracker.