The only thing I can say is that the Stance of the Iron Tyrant should function like most PrC granted stances. That means including the following line...

"As a Swift action, when in an Iron Heart stance, an Iron Calamity can forgo the effects of that stance to enter the Stance of the Iron Tyrant."

Otherwise it's a little TO good. DR 10/non-metal and destroying weapons in addition to what I get from my stance? Sign me up!