Talk:Armor bonus

Does anyone know for certain exactly how mage armor and/or improved mage armor stack with worn armor? I seem to remember that once upon a time improved mage armor was pointless if the total AC from worn armor was already 6 or more. However, according to the in-game display, mage armor spells now essentially replace the armor enhancement, but will still stack with base armor. If this is indeed true, then improved mage armor is arguably broken at lower levels, and is only totally irrelevant once into epic content. Anyone know for sure?