Unfortunately, these DE chains are limited to certain zones that have the large DE chains - this kind of defeats the object because now instead of being funneled into one zone - Orr - you're now being funneled into one other zone, which is the one with the large DE chains.
Honestly, I don't find it efficient to farm karma in lower level zones. I think the downlevelling should bust you down harder so you have far more of a challenge trying to do the content, then they can raise the rewards to near-equal Orr levels.
Currently it doesn't actually seem worth it unless you like the zone or have a chain event / rotation farm organised plan going.