what it really is is the "scatter" of the missiles in radians to each side. If you guys want to get super pedantic (like I did with the archers and slingers), you can try to figure out a historic accuracy using that, and then tweak how deadly the hits are with battle_config..
That will; explain the smaller scatter with smaller values! , thanks.
Anyway was not intending to do that. Too much work + you need time to research those things.