only getting 50 credits

Hello to anyone who may read this. I love the new halo reach game and play it quite often but perhaps not enough to be an expert on it.
that being said I have noticed that when I play matchmaking or firefight online I will usually get a good percentage of credits about 1000 or so on average, but when I play local with lets say my brother whose profile does not connect to xbox live I only get 50cr from the same match that his profile may get 1500 from. whats up with that? and how are the credits received actually calculated? are they a percentage of the points earned during play or what?
hope some of the masters can answer.

There’s a section about credits in the Halo: Reach Support FAQ:

Hope that helps!

Hey, i just read what you wrote. I have the same problem, but when I went offline for the first time i was DEMOTED! I was a major grade 1 but then i was demoted to a sergeant! Did this happen to you too? And do you know know how i can fix this?