Let's say I've got two daggers. My mainhand one has +30% backstab damage and my offhand has +15% backstab damage. I'm backstabbing someone. Would the hits go +30%/+15%/+30%/+15% and so forth or would it go +45%/+45%/+45%/+45% (etc.)?
Oh, and a random thing: god damn it, why does ALL THE GOOD EQUIPMENT HAVE TO BE ****ING MAROON?!? Why would you do that, Bioware?