imo its BROKEN currently
I'v been in 5vs5 games, where humans got S3 while aliens with MORE kills had S1 .. all it takes is aliens constantly joining and leaving, game adds to stage kills at once, but never/VEEEERY slowly subtracts, Me and karvajalka killed >10 humans in 10 minutes and STILL were 1-2 kills from S2 .. while humans had S3 all the time, its VERY BROKEN.