Harmony - Troop Symmetry

I try to test the mod a little bit every day, making corrections and so on. Right now, I'm facing a problem with magic spells that deal direct damage. If you don't mind, could you help me balance them? Here's my logic:
Direct damage spells that target a single unit are usually stronger than those that are lower level (i.e., Lightning is stronger than Magic Arrow, etc.).
Area-of-effect spells are different; they are equal in damage, but the higher their level, the larger their area of effect (i.e., Fireball is as powerful as Armageddon, but Fireball hits a 3x3 area, while Armageddon hits the entire field; Stone Spikes are as powerful as Meteor Shower, but Meteor Shower has a larger area of effect than Stone Spikes).

I also made the spell calculations dependent on their element:
Earth - strongly depends on level and strongly depends on magic skill.
Water - weakly depends on level and strongly depends on magic skill.
Fire - strongly depends on level and weakly depends on magic skill.
Air - weakly depends on level and weakly depends on magic skill.