Mez Resistance inconsistency

[Swaglinger]

Looking at my character's combat attributes, I noticed that the Status Effect (or "Mez") Resistance I'm getting from enhancements and sets is less than it says in their description. For example the Unique "Aegis: Psionic/Status Resistance" enhancement is supposed to reduce the duration of status effects by 20% but according to the Combat Attributes window only reduces by 16.67%, same with all other set bonuses.

 

Is this intentional?

[Omega-202]

It has to do with how Mez resist and all other "reductions" are calculated.  What is actually happening is that you get 20% reduction, which is then calculated as:

 

1 ÷ (1 + 0.2)  = 0.83333...  or in other words a 16.7% overall reduction

 

All other reduction enhancements work the same.  200% recharge reduction is equivalent to 1 ÷ (1+2) = 1/3.