The only reason a manufacturer would ask for a seperate ground rod at their equipment is: Ignorance of proper grounding pratices. At least they asked for it to be bonded to the building grounding system/grid.
Every service should have a single grounding system (ideally a ground grid in non-residential buildings). It make take multiple ground "rods" to create the system but that should be part of the design not simply because a machine manufacturer wants one.
Just because you can, doesn't mean you should.