I would assume that any modifying ability such as this modifies BASE. You are assuming that it modifies you're already modified armor rating. In the vast majority of such mechanics I've ever encountered, it doesn't work that way.
Your second calculation is the correct one and I would feel safe assuming that this is working as intended. The other way would be weird and would open up all kinds of cans of worms. For example, if there were multiple +% abilities, which applies first?
Unless explicitly stated otherwise, you can safely assume ANY game mechanic that modifies an attribute always modifies the base attribute.
Last edited by jfunk; 02/07/14 04:47 PM.
