But you can't<em>get</em>that last +6 because they're a part of Dragon Apotheosis, not Ability Boost.<br/><br/>And the Dragonfire Adept invocation's just to get through to grab the natural armor boost, if you really want it.  Two feats for +2 natural armor's as good as Dragon Disciple gets you, while just getting Ability Training in strength is considerably more efficient than Dragon Disciple's Ability Boost.