Roundown and subtract time (Including Midnight)

Giganews Newsgroups
Subject: Roundown and subtract time (Including Midnight)
Posted by:  J.W. Aldridge (jeremy.w.aldrid…
Date: Mon, 28 Jul 2008

I have info/times that come in EST starting with column F6 down.

I am trying to do two functions here but cant seem to get my formulas
to marry.

a) I want to round down the time to the beginning hour.
b) I want to subtract an hour from whatever hour is given. = -"1:00"

Issue: If the hour is midnight 0:47, it should reflect 23:47 but it is
not when using this formula. It coming up ##### for any time during

Midnight hours are the only issue.