RetainVhdCopiesOnSource option

what does the -RetainVhdCopiesOnSource option actually do?

i've tested it in conjunction with the move-vmstorage cmdlet and it does not copy the VHD file as it suggests, it moves it

i also can't seem to leverage it with move-vm or when combining move-vm & compare-vm cmdlets together, error is:

Compare-VM : A parameter is invalid. No virtual hard disk can be found with given criteria

i read on a different thread that -RetainVhdCopiesOnSource is actually just for snapshots but TechNet does not state that