Well they have gone and done something with this spell that was probably not intended. It has always been clarified that "Armor Enhancement bonus" increased the "Armor Bonus" to AC, and that "Shield Enhancement bonus" increased "Shield AC bonus"
This spell however
"your armor gains a + 1 enhancement bonus to
your AC. An outfit of regular clothing counts as armor
that grants no AC bonus for the purpose of this spell. This
enhancement bonus stacks with itself to a maximum
enhancement bonus of + 5."
So we now have an Enhancement bonus directly to AC...provided by armor. That probably still hits the +5 enhancement bonus cap...maybe?
So i guess the questions are,
1)Does this stack with magical "Armor Enhancement bonus"
2)Does this hit the armor +5 enhancement bonus max if combined with magic armor
3)Does this add a new "type" of bonus available to AC
Thanks