So heres the thing, while youre in DoS or Stalwart stance, the Bonus to Dodge AC does stack with basically everything, even with same amount Dodge value items. ( For example Tier 2 Stalwart Stance stacks with Epic Grims Bracelet).

When youre in Earthstance the Natural Armor Bonus does not stack with Items like Epic Seal of Earth.

Imo thats a bug since it should work like real Natural Armor like the ship buffs, and not like Item Effect.
Not paying that much AP for a useless stance, if not even the AC stacks -.-

Haek