In the previous version of the D&D game, having levels in a prestige class never caused you to pay experience point cost for being a multiclass character with uneven class levels (the prestige class levels didn’t count when checking if you have a penalty). The section on Prestige classes in the new Dungeon Master’s Guide no longer mentions that you don’t suffer an experience penalty for having levels in a prestige class. Is this a change or an error?
This is an error. Having levels in a prestige class won’t give you an experience penalty.