It would be great to see this tested. I'd do it, but I'm skeptical that I'll get meaningful results.
I'd like to know whether the zoomed-in focus area is taken into account when the zoomed-in focus box isn't showing. That would seem sort of strange to me - to show the normal autofocus box but apply the finer, zoomed in setting. Means you have to eyeball what you're actually focusing on.
I've noticed that, with the zoomed in autofocus box on, it's not possible to cycle into the levels or highlights/shadows view in the EVF or touch screen. The behavior I would prefer is to be able to leave the zoomed-in autofocus box on, so it's easier to see exactly where your autofocus area is, but also allow you to cycle through the levels and highlights/shadows views.