Well until bungie makes a proper announcement about this I'm going to have to believe that impact and defense are factored in for regular gameplay and agility/recovery/armor are factored in for IB mainly because it's the only logical explanation that doesn't say that the IB is broken. And I mean honestly the guy is -blam!-ing good he evades and has clean shots skill matters it's not who has the bigger gun you know? But his gun may be saying 20 crit damage but that's A: half of my crit damage and B: a whole clip to take out one guy.