Smite and DR / epic

[Kargoth Kargoron]

Should a character's smite ability overcome damage reduction/epic? I am thinking of at least house ruling that my player's paladin can only overcome DR/epic when he hits epic level.

[wraithstrike]

By the rules it does. I am thinking of a similar houserule however. At the very least he would need to be level 20 since that is about the time that Epic level threats would come into play.