I once debated for four hours with an individual in Seattle MIDO about permits for flight testing. Smart guy, usually helpful, but he had a hangup.
And that MIDO office was ignoring HQ policy that clarified.
That was in the era when FAA had issued a permit for a prototype airplane to fly from Oregon to OSH but it never arrived. FAA was probably sued.
One outcome was a standard policy of limiting permits to 500 nm radius. So one day I find myself directing an avionics flight test out of the Seattle area, in a good DC8-73. One item in the testing was to be performed in clear air at altitude, for extra safety.
But weather was deteriorating in the region, so we decided to go to Great Falls MT if necessary. Oh! that’s somewhat over 500nm. Fortunately weather improved so we stayed local. (Do that test over the ocean for extra safety, the rest of the testing was at low altitude.)
In making sure the permit covered what we needed, we did not think about the limit, we had no need to go far and didn’t think that weather would deteriorate. But FAA were silly in not differentiating between a proven fast airplane with modest modifications and an experimental category slow airplane.