So I created a spell, based on something I read on the forums, that has the following effects:

1. Fortify Magicka 20 Pts for 1 second on Self
2. Damage Health 20 Pts for 1 second on Target

I had the spells created at the Gnisis Temple. I tested the spell, and, sure enough, when my magicka was depleted for the spell amount (ex. 30 magicka), my magicka was then increased by 20 points (permenantly, as if restored)! So the spell only cost 10 Magicka!

Well, I Recalled to the dungeon I was currently clearing, but now when I cast the spell, the 20 magicka increase only lasts for a second, then drops back down.

Is there any reason this spell would behave differently based on location?

I'm trying to find ways to reduct my magicka cost for damage output, and this seemed to work at first, but doesn't really in practice. Are there any other suggestions for this? Like a Weakness to Magic + Damage Health or something?