Extra armies for territories
Warzone can be configured to give extra armies based on the number of territories that players control.
For example, if this setting is set to 3, players will receive one extra army per turn (income) for every 3 territories they control.
These extra armies apply only after the base armies per turn has been reached. In other words, players will receive whichever is larger: the base armies per turn or the extra armies per territories - not both.
This setting is disabled by default. Therefore, most games (including the single-player levels), do not use this.
Let's say that a game has a base income of 5 and also gives out an extra army for every 6 territories held.
This means that even if you have 24 territories, the number you'd get from the extra armies is only 4 (24 divided by 6), which is less than the base of 5 so it does nothing. You'll still just get 5 armies per turn plus however many you get from bonuses and cards.
However, once you get 36 territories, then you'll be getting 6 from the extra armies, which is greater than the base of 5, so you'll have one additional army. That means you'll have 6 armies per turn plus bonuses/cards.
Every 6 territories you get above 36 give one more army per turn.