One other thing to consider--
As I had nearly run out of my wife's decaf, I did not have enough for a full pot in the 8-cup stovetop. Being a good engineer, I measured the water volume to make sure I filled it to the correct point to match the weighed-out coffee.
On my Yama 8-cup stovetop, the 8-cup line is more like 35-36oz. than 32 oz. Makes sense why I am getting better results with loads of ~62g (if you believe the 7g per 4 oz. water).
I'll be measuring the 5-cup tabletop before I use it next. I'm almost ashamed that I didn't do this sooner. That said, my coffee intuition was working, because I could tell that 56g was not cutting it in the 8-cup.
EDIT: On water temps--B|Yama, are you pre-heating the water before it goes in the pot, or are you heating it entirely in the Yama? Gas or electric stove?