Good question!
So eventhough the power shelves are "passive" there is an i2c bus on the modules that allows us to read the voltage, load etc.
that i2c bus is fed by the modules in the shelf.
Now, if I have only one module in the shelf and that module is unpowered, that means the i2c bus is not powered either, does that mean that there is a module, but not working, or is there no module present to start with, that state can't be derived.
So if you have say a need under a certain config for 4 modules. I would load them 2 on 2, this so the shelf is always powered and we can derive the ok/fail state properly of a certain module.
For power distribution it doesnt matter where the modules are, it is just for that module mgmt story that you would spread them out...
xander
