1. The description for Enlightment reads: "Optimizes both white and black magic capabilities and allows access to both addenda for your next spell."
2. The part that says "Optimizes both white and black magic capabilities" seems defunct.
3. Activate Dark Arts.
4. Activate Enlightenement.
5. Cast Reraise III(costs 180MP while in Dark Arts; 150MP without any Arts; 135MP with Light Arts)
6. Notice that Reraise III, despite being cast while under "Enlightenment" still consumes 180 MP. Not only this, but the casting time is still as if Dark Arts is in effect.

It seems the description for Enlightenment is either an error or the JA does not give the bonuses that the description states. It DOES allow access to both Addenda for the next cast but does NOT optimize White and Black Magic for your next spell.