Good evening ZMike,
when you open the scenario game files(for example the scenario "egypt mayhem.xml") you will see in the first few code lines:
<scenario>
<difficulty value="4"/>
....
I think that has something to do with the difficult settings. Al least it would fit because the npc - players are named "cpu-mega" and the difficult level 4 is called "mega".
I hope I can help you with this.
with best regards
Mike