All the command squads are locked at the minimum size of the equivalent unit. Power armor, 5 models, Terminators, 5 models, bikes, 3 models.
I think it's a little unfortunate, but it is probably what they intended.
I still see a use for 3 RW command just behind a few units of regular RW bikers (the TL boltguns of which the Salvo would certainly affect) with the Devastation banner laying down ridiculous amounts of fire.