Wow, usually the FAA chief council is pretty good but it seems like they're doing quite a few legal gymnastics to arrive at this point.
This interpretation could easily have gone the way, so I am a bit curious about the "back story," if there is one. FWIW, I have a theory...or rather just a WAG:
Chief Counsel interpretations often reflect Flight Standards policy considerations almost as much as regulatory language. In many cases, it's not as simple as "well, this is what it says." We can point to both old and new ones in which this is the case, especially in Part 61. The safety pilot thing has always been interesting. A PIC safety pilot, under a strict reading of the rules, is
not a pilot acting as PIC in an operation that requires more than one pilot. Yet, for decades, the Chief Counsel has clearly said she is. OTOH a safety pilot really
is someone conducting a flight in an aircraft that includes a landing at a point other than the point of departure. But the Chief Counsel says he's not and can't log cross country time. But one can come up with decent (although disputable) policy reasons for both. There are plenty others.
The original purpose of supervised solo was to allow a pilot who could not meet insurance requirements for flying a twin to meet solo requirements. If the pilot can meet insurance or FBO policies to fly solo, there's no reason to use the rule. But it would be a problem to administer and enforce a reg that said, "if they'll let you fly solo, you must and can't take advantage of the rule."
Second best to have a disincentive to pilots who can solo simply being too nervous to do a long cross country without a CFI on board but happy to do some local night solo flights (or vice versa). Have them make a choice and stick to it.
But, as I said, just a WAG.
