As for clearing the entry fields, I'll wait for your opinion regarding

the way things currently work

I've been using this new feature for a project.
The first time that I tried it with multiple nodes, I didn't expected it to do what it did :
for me, the coordinates were those of the center of the bounding box, and thus when modifying the values, I wanted to modify the coordinates of the center of the bounding box.
But finally, I think the solution you choose is better than what I first expected the tool to do. It will work the same way than selecting 2 shapes with different fill colors.

And just another issue :
when changing units with multiple nodes, there is the same kind of problem than the "tabbing" bug : the values are applied.

Steren