I think that in this case sceptre is referring to an imperial sceptre (symbol of imperial power) rather than a long sceptre / staff. We know of imperial sceptres with eagle tips (Bust Type H in RIC V) and we know that they exist with orbs on the end. I don't think the Imperial sceptres were long but short enoough to be carried in the manner on the first coin.
Image of Imperial sceptre supposed to belong to Maxentius found recently illustrated below:-
Regards,
Martin