Worn Item: Imp Dodge III
ex: ((100/100 + 255/255)) x (1 + .3) -> (1 + 1) x 1.3 = 2.6% dodge
vs.
Worn Item: Imp Dodge III AND 18% Dodge aug
ex: ((118/100 + 255/255)) x (1 + .3) -> (1.18 + 1) x 1.3 = 2.8% dodge
not quite correct, using 100 dodge skill and 255 agi with imp. dodge 3 it would look like this.
(100/50 + 255/100) x (1 + 0.3) == (2 + 2.55) x 1.3 == 4.55 x 1.3 == 5.19
add a +18% dodge mod and you get..
(118/50 + 255/100) x (1 + 0.3) == (2.36 + 2.55) x 1.3 == 4.91 x 1.3 == 6.38
The factors of 50 and 100 for skill and agility are not accurate, this is just the structure of the formula. PM me if you want specifics.