Being lvl 14 means the lvl modifier will have a devastating effect on you if you fight with anything bosslike lvl 17 or higher. Then again, having AP for 12 battles is quite enough, since all battlezones have up to 11 stages (I think). Even if not so, the hero cannot regenarate spirit and HP (you can compensate that with HP/spirit potions), but every 1 hour a new AP is generated, regardless of the battlezone type you are in.