Miller,
You are dreaming a fantastic dream if you believe there are 3000 people reading a double gun board, let alone 3 million. But, I digress.
Good to see that you finally got around to using the correct term, "Service Load", as used at the proof house. It would seem to show that ignorance is correctable.
Kennet has pretty much blown your theory that "anything goes" with proof powder, as long as it makes X amount of pressure, out of the water, at least when talking French proof, but, hey, I'm open to the idea that you could prove this happened somewhere else.
So, prove it.
As to the French "catching on", to use your words, every single new French gun I ever ordered had that neat little stamp, PT, under a crown.
So, when did they "catch on" and stop marking their guns with the powder used?
I'm curious to know.

Best,
Ted