Power (Weapon) Encounter (Minor Action)
Until the end of the encounter, your divine challenge power targets two creatures in the burst instead of one.
Champion of Order's utility power:
Free Action Personal
Effect: Until the end of the encounter, every use of your divine challenge targets two enemies rather than one.
My reading is that you're capped at two DCs, but I've seen various people comment on how good the interaction is between these two things and I was hoping someone could tell me why.
Let's assume that the DM and the player have already figured out how multiple DCs work in play and just focus on the number.