I set my zombie scaling to 28.0, and I saw 3 hulks in the first day in the starting city. That same happened with value 0.10, too.
Static spawns, spawn rate 2.5
Version 0.C-3467
Explain that. 
Edit 1:
From the savegame folder, worldoptions.txt
[QUOTE]
#A scaling factor that determines average time in days between monster upgrades. Set to 0.00 to turn off monster upgrades.
#Default: 1,00 - Min: 0,00, Max: 100,00
MONSTER_UPGRADE_FACTOR 28.00
[/QUOTE]
I assumed that based on that description and the “28”, monsters would upgrade every 28 days on average. Is this a false assumption? Or did I make them upgrade 28 TIMES FASTER than normal?!
Edit 2:
…I didn’t think that one through, did I?
I mean, at value 1.00, they would upgrade once per day, is that so?
That would mean at 28.00, they would upgrade… in 1/28th of that time? Or once every 28 days?
Why can’t you make descriptions that can’t be interpreted in multiple ways? 
Basically what I want is super slow evolution. But I’m still confused if I need a value of 0.01 or 100.