I don’t think this is possible because there’s hardcoded non-moddable 20% jitter (you can search for it on forum / discord).
This 112 - 168 % Cold damage in the screenshot (I stole from someone on Discord):
100 * 1.4 = 140 (1.4 is because of 40 attributeScalePercent)
and then hardcoded 20% jitter makes it
min = 140 * 80% = 112
max = 140 * 120% = 168
with 20% jitter Max is always 50% bigger than Min because 1.2 / 0.8 = (1+jitter) / (1-jitter) = 1.5 = 168 / 112
If you wanted let’s say 112% - 200% (so more max damage but the same min damage) you’d need (156 is new average value):
(200 - 156 ) / 156 ~ 28.2% = new jitter
but you cannot change it (can be hacked though as you can at the end of my post)
Unless they managed somehow 
but that’s an exception to the rule probably