I guess what I'm trying to say is if you wear anything - robes, clothing, etc. - then I can see the AC 10 but to be in your cute bikini undies and still have about as much AC as you would have if you were wearing Light Armor seems weird.
Why would cloth provide any armor, let along an increase that huge? The basic light armor is either a simple leather jerkin or padded armor, neither of which would provide you with significant protection, so an increase from 10 to 11 feels appropriate.
