Proc on Chosen Vanquisher/Overlord armor

[Skullgrin]

Was looking at the different set bonuses on Chosen armor sets and noticed a slight discrepancy between the 4 piece bonus on the Vanquisher set and the 2 piece bonus for the Overlord set. Both have basically the same ability (10% chance for +7% to parry, block, dodge, disrupt for 10 seconds) however one is active while the other is defensive. My question is, how does this work if you are wearing 4 Vanquisher pieces and both Overlord pieces of armor?

Are there two separate rolls at 10% to get the proc?

Do they stack somehow and you can get both procs at the same time Resulting in +14% to all defenses?

Some weird combination of both of the above?

Are they actually the same proc and there is no additional bonus for having both?

Any insight would be appreciated.

[wargrimnir]

Abilities do not stack with abilities.
Procs count as abilities, and shouldn't stack if it boosts the same values.

[Gangan]

Theoretically the chance to have at least of the buffs up should be higher, as they trigger at different conditions.
Don't know if it's worth though, I recently just got my first overlord piece (took me just two weeks ) and couldn't test how often the proc is triggered.