Eric, you have discovered the gold, now follow through with it. As you said, the sound wasn’t affected and I bet it felt way freer. Will you be able to play your same range right away? Probably not but maybe.

You have said everything that I would have said to you already about anatomy and placement. The fact that the mp keeps wanting to move back is because you have been doing it a long time and probably happens as you ascend am I right?

Start from Largo with the new placement and take it really slowly.

This will not affect what you can already do and if you are gigging, happily use whatever setup you need to to get through the gig, just do plenty of repetitions with the 2/3 lower position in the practise room.

Well done,
Greg