IIRC, that's more or less what happened. Siege of Mirkwood didn't add a new crafting tier (T7 is Westfold, from Rise of Isengard). I don't know if Mallorn was added then or if it was already present with Moria (I tried to research this, but info from circa 2008 is unfortunately hard to find), but basically Supreme crafting was the top tier through two expansions.
Originally Posted by Yula_the_Mighty
Cainwen Ciaphas, Captain of Crickhollow, HERO OF MIDDLE EARTH!!!
I will not be pushed, filed, stamped, indexed, briefed, debriefed, or numbered! My opinions are my own!