I havnt played aoe in a long long time, so ive lost touch with it and wouldnt be sure exactly how team games are caculated, but singles are easy
OP = opponants rating
UR = Your rating
Net change = Net change in your rating if you win.
NC = 16 + ((OP-UR)/25)
Example
Your opponants rating = 1700
Your rating = 1600
NC=16 + ((1700-1600)/25)
NC=16 + (100/25)
NC=16 + 4
NC=20
So if you win you gain 20 points, to find out how much you would lose simply take 32 and subtract NC, or in this example you would have lost 12.
In english, basicily for every difference of 25 the points won or loss changes by 1. The so if you rrated 1700 and your opponant is rated 1725, you gain 17 for winning and loss 15 for losing, because he is 25 points ahead you gain more then you lose and the difference is 1
If your opponant is rated 2000 and you are rated 1700, you gain 28 points for winning, and loss 4 points for losing. To clarify a potentialy confusing point, when you WIN 28 points, your opponant loses 28, because this was an upset as far as rating is concerned, the point change is large. When you LOSE 4 points, your opponant gains 4 points, as this was an expected result, the difference is small.
If your opponant is rated 1600, and you are rated 1900, you gain 4 points for winning, and lose 28 for losing
If you are rated 2000 and your oponant rated 1500, you gain 1 point and lose 31, this is a special case.
When the difference between the two scores exceeds 375, its always 1 point if the higher person wins, and 31 points of the lower rated wins.
The entire validity of the system is based on the concept that for every point won, a point is lost, if you take that away the system becomes mathameticaly meaningless, thus when 5 people win 16 points and one loses 16 points, in the case of a wonder win, or allying up against a dropper, the system of ratings losses its integreity and is devalued of meaning.
As this happens alot in AoE, the entire system is highly flawed and worthless, RoR is much better in this regard.
Anyway, thats my own personal beef, hope I answered your question, team ratings is based on singles but is abit more complex, generaly the higher rated your opposing team the more you stand to gain and the less you stand to lose.