Wow that was fast I must say the 80/60/40 % cost is even better balanced. Here is a somewhat good English translation:

Teleports your hero to a friendly unoccupied town.
None: Nearest town. Your hero expends all remaining movement points.
Basic: Nearest town. Your hero expends up to 80% of her total movement points.
Advanced: Any town. Your hero expends up to 60% of her total movement points.
Expert: Any town. Your hero expends up to 40% of her total movement points.

In my previous post I tried to hint at another difference between the different levels of the skill of the Earth Magic spell: a restriction to the towns you can teleport to based on the Map level your hero is currently residing in - surface or underground, meaning if your hero is on the surface map level he can not teleport to an underground map level town unless he has the expert earth skill. This might make using a Subterranean Gate more important and somewhat restrict the Town Portal spell's power. Can something like this even be done?