I don't know. I wasn't aware of a 200Ly threshold.
I simply looked up the best locations to get rares in INARA. I chose a good spot that happens to be a distance of 120Ly away from my power's region... or (by chance) 180Ly on the far side of the region. So of course I dump rares at the far side. And it looks like it is very popular for other cmdrs too.
The Old Worlds are about 170 light years from where I'm operating, and they've giving me, on average, about 30 merits per ton. On the other hand, there's a system 40 light years away that gives me only 7 merits/ton.