I am using Project 2003. XP, OSuite 2010

We do plant outages on a 24hr/7day schedule.

I have my timescale set to 2-12 hr shifts per day. Exactly as I want to show it.
When I enter the duration for a task, either in the columns or in the Dialog Box, i get some issues.
When entering 24, or 48 or 72 hrs, my activity bar shows nicely as it should.
However, when I show 36 hrs i get a activity bar that is 48 or 4 shifts long.
What am I doing wrong?
Got the Task set to Finish as Soon as Possible, Effort Driven, and Fixed Units.
Got the Project data set at 24hrs on the calendar

The solution to later versions should be similar and knowing that should help me back into @003.

Thanks in advance.