Defender of Siberys and Shield Prowess

[ValidorKanston]

I posted this in the Epic Destinies forum, but there's been no answer. Not level 20 yet (only 18), so can't test this myself.
Does the 40% shield bonus from the DoS III Superior Defensive Stance stack with the 50% bonus from the Shield Prowess ability?

[JonD]

I posted this in the Epic Destinies forum, but there's been no answer. Not level 20 yet (only 18), so can't test this myself.
Does the 40% shield bonus from the DoS III Superior Defensive Stance stack with the 50% bonus from the Shield Prowess ability?

Yes.