Administrative punishments do not include time. NJP is not the same as an administrative punishment.
I guess it just depends on how one uses the term 'administrative'.
Non judicial punishments don't involve juries or judges, and don't need to involve witnesses or probative evidence (though they may well often do include these things). That sounds pretty 'administrative' like to me.
But, yes, the formal term is probably 'Non Judicial Punishment'. In the end, non judicial punishment (administrative by most, but not all definitions of the term) can have a punishment of one year in prison (but that place may not technically be a prison).