It is the avg of your team score. during the game if you hit tab it has a totals on the very bottom of everyones score. they take that total score number and divide it by the number of people on. So say you have someone with 100 pts and they leave before round ends. the points are still included in teamscore but they arent included in number of people

. if you happen to have an avg of 20.8 and you dont win you will have a score of 21. however if you do win its 2x avg of total score at end of the round. so if you have 20.3 avg team score x2 you get 41

. so thats how you can have a possible odd score at the end of a round. The points you accrue during the game are team points that are added to the teamscore to help out your final score.
so during the round you get points for someone using your supply box to repair/resupply/heal and you also get points as your team kills those in your uav and spotted (though im not sure how many have to be killed for you to get a point). The thing people do is confuse your final score with in-game score.
Did I confuse you or do you understand?
oh and has "Tard er Nard" said

if you do get teamwork points like killing someone of opposite team be it arty or anything or cap a flag you will get - points added to your global score. Meaning you take your Total score of Commander+team+combat you will get your total score however total-global will be your missing points which is all those flags and kills you had as commander. So dont do any flag capping or repairing of assets (outside of supply crate as that doesnt hurt your global). I have lost over 7000 pts because of this. I would have well over 30k pts if I wouldnt have done all that capping etc.