Rogue, I also wondered if the powers that be think this could be an effective way for the elders to control a larger congregation (in areas where they've sold halls and combined congregations). In a large group it's harder to know what individuals are up to. Perhaps they think enforcing this small service group arrangement will help them continue to police the sheep (in the absence of any better idea).
I think so they really are emphasizing this not just as a FS arrangement but as a way to keep in touch with the Elders. The FS group overseer "is responsible" for his group. It extends the hierarchy of control down one more level but tries to make it seem like just a friendly FS arrangement.