Feature "Conquest" specifically "Angel's Blessing"

I'm playing on s1611 Eunice and my in game name is "naomi". I have a question about the game feature called "Conquest". Do the % benefits from "Angel's Blessing" add up? So, for instance: do 200 +2% DEF "Angel's Blessing" add up to a 400% increase in DEF? Or, is there a limit to how much of an increase the "Angel's Blessing" bestows.

The reason I'm asking this, is because I have been buying the double percent "Angel's Blessing" with diamonds, and I don't want to waste diamonds buying something that doesn't do anything, or stops doing something after a certain value has been reached. Anyway, hope you'll give me an answer soon. Thanks a lot! Ciao!