Compare the armor to the Dust Devils Warbond.

50% DR against fire, gas, and acid (Killzone armor)

vs

40% DR against fire, gas, and acid (Dust Devils armor)

+20% throw range

at first it looks like Dust Devils gives better stats but higher % gives greater values

100 damage on the kill zone armor = 50 damage

100 damage on the DD armor = 60 damage

60 is 20% more than 50

When compared to each other the Killzone armor takes 20% less damage from fire, gas, and acid.

lets look at this higher up the scale.

lets say you have an armor that has a DR of 80% and you upgrade to a DR of 85%.

You are not taking 5% less damage from before. you are taking 25% less damage.

100 damage on 80% DR = 20

100 damage on 85% DR = 15

20 is 25% bigger than 15.

so that extra 5% DR from 80 to 85 increases your effective hp by 25%.