Increased Experience Using Skills/Spells

The experience gained from using skills and spells is now considerably greater than it was. Using a spell or skill at the level it was gained will also garner the player more experience than using it in later levels. This experience bonus will stop at 10 levels past the point that the spell or skill was earned.

Example: If a spell is earned at level 10, a player will get the experience bonus up to and including level 20, but at a decreasing rate.

Thanks to Gauther for the idea and Lina for the code.