Blocking 120% more damage means that you're blocking 120% more than your original damage value, not that you're blocking 120% of incoming damage.
Ah I see. Yes, that makes sense.
80% cap I believe. Some people love it some people hate it. If you hate it, hopefully you are on PC.
I don't really mind either way, I just wanted to know what the haps were, since a cap of 80% would mean that I can spend the redundant 40% enchantment slot on something else.