Return of Reckoning

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.

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

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.