Ignore def doesn't stack

Codex ignore def works now.

Tested using regular attack on Chief Oblivion Guardians (PDRate 20%). Other sources of ignore def: Combat Mastery (40%), maxed Ambition (10%).

Using Leafre Set (30% ignore def. no relevant skills affected by the "CO" effect), I was hitting 96% of my range.
Using Mushroom Shrine set (no ignore def), I was hitting only 90% of my range.

I don't have a weapon with ignore def, to test whether they stack.

I hope this is true. I'd like to start using something other than the Zak Set for once.
LF> More confirmation.