EXP Penalty and Leveling Places

[Tubble]

Howdy everyone! I had a couple questions I hoped you guys could answer. I am playing an SK with my shammy brother and whenever we group, we both get the same experience. Aren't SKs supposed to have an xp penalty? Also, we are both 13/12 and currently killing Caimen in Oasis. Would another place such as unrest give us more xp per kill? Thanks guys and having a great time so far!