I'm not sure where I was unclear in my explanation, but we're not on the same page here of how this setup works. I'll try to expand on this or find a good explainer video later when I have time.
I think we are on the same page.
Standard tank heats water to 120.
Instead, we are going to keep the tank at 140.
Mixing valve will give us the standard 120.
This increases the amount of 120 we can use each time.
Same page?
The question I have is it more energy efficient.