That's pretty much what I thought, as I knew you liked to dig into the patent files.
I would guess they are very close, with maybe some trivial additonal variables thrown in etc.
At this point someone with a dyno could take those relationships and play with different fuels and either validate them or demonstrate exceptions.
My guess based on my previous experience and what you've added here is from a performance point of view the improvements above 104 octane will be small, except for those running high boost and with on the edge tuning. In that case they probably do not rely on the stock ECU anyway.
If how ever one of the folks who can do ECU reflashes wanted to they could optimise a reflash high octane map for 112 or above, with a low octane map at typical values to give the ECU more dynamic range.
I love puzzles !!