Seems to me the receptionist's got a good idea there. Keeps people from showing up in the wee small hours just after midnight.
I wonder if this confusion about a.m./p.m. was one reason the military adopted a 24-hour "clock."
Half past midnight is zero thirty hours and half past noon is 1230 hours Morning hours are zero one, zero two hours etc.
One in the afternoon is 13 hundred hours, 6 p.m. is 18 hundred hours etc etc