Stage cutting a branch

The Japanese Maple stream with Peter Warren is one of my favourite. I have been thinking about the stage cut that Peter makes by removing a “V” from above the branch to aid in the healing processes.
If a “V” was removed from the underside of the branch instead of the top, would healing be faster or slower?

Healing should definitely be faster. By doing so you are leaving the lower section of the branch intact, thus reducing the chance of losing the branch immediately and more importantly dieback along the trunk. The remaining section maintains flow of nutrients and water which allows for faster healing as resources move up to the branch and hopefully around on the way up the trunk.