Sorry to not be able to answer your question, but i have one of my own to ask also.
With battling, you need AP experience to level up specific skills. Do i get that by doing that specific attack, or do i not even need to use that attack to get AP experience for it. I'm not sure about this, because at the end of some battles, it says: 50 AP, as a reward, which leads me to think that if you wanted a certain skill raised, you wouldnt even have to actually use it once, but get AP xp from battle's endings.