Maybe this can solve neverending rounds?
Not sure about numbers but here's logic:
If
    whole team player number > 20 (meaning 20vs20)
then
   Check people alive on each team (every 10 seconds for example)
   if there is at least one team with less than 4 players (3 or less)
Then
   spawn flags (MOTF).
What do you think?
PS: Just a thought that came to mind, haven't been thinking about it a lot but so far seams reasonable.