See the code for yourself here: http://afkmods.iguanadons.net/index.p...
Yes I did my decimals wrong, but otherwise I can't explain the math on this page: Scroll down to "how settlement raids work":   / psa_settler_recruitment_and_raid_chances  

My Twitch:   / scotchandsmokerings  
Mods Used: http://oxhorn.it/modsused
Oxhorn's Free Fallout 4 Settlement Happiness Calculator: http://oxhorn.it/happinesscalculator
My Fantasy Novel: http://www.cloranhastings.com/
ALL of my settlements and their status: http://oxhorn.it/settlementstatus