That game had a broken system. In every battle you could just get your stats up by attacking yourself, then healing yourself.
Example.
On the NES version, You select Firion to attack with Fire. It's now Maria's turn. You now cancel it so it's Firion's turn to select a command. You keep doing that over and over again, with him selecting Fire, until you get bored so you now finish the battle with normal attacks. It says that you leveled Fire.
That's because every time you chose Fire, it added experience to the spell but didn't take that experience away when you canceled it. They've changed that in future versions. But imagine that. You could level up 16 spells up to LV 16 in 16 battles.
