ONCE in a great while you will get information on an approach plate that makes you think
some are: MANDATORY ALTITUDES
some are at or above
We learned along time ago that you maintain your last assigned altitude UNTIL Absolutely ESTABLISHED on a PUBLISHED segment of an instrument approach. (Bless those poor TWA guys at IAD).
I do have one question for the first poster...Was your approach clearance: CLEARED ILS 28C? Was it: cleared LOCALIZER 28c, or was it cleared apch...
And here is a really good clue for next time. Get the phone number for apch control (maybe from clearance delivery on the ground) and call them up and ASK THEM what they expect you to do.