Well, it's funny nomenclature for you: in Makedonia there seems (if memory of the discussions on the team, serves me) to have been a distinct difference between this "junior elite" (Peltastai Makedonikoi) who were mostly known for their elite status because of their soldiering-skills; and the Hypaspistai who were much closer to the king (namely his personal foot-guard).

That indicates a distinct social & political status difference between the two fighting forces. Also the Hypaspistai seem to have been some sort of Military Police.