Thanks for the reply,
I have found out how to ensure the actual start of a task will be maintained regardless of what timescale is selected. Under File-Options-Schedule 'Default start time' and 'default end time' I had selected a 24hr period i.e. Start time = 00:00 and the end time 00:00. This was making the start time and end time round UP to the minimum time interval on the timeline. When i changed the end time to 23:59 the start and endtimes did not roundup anymore and stayed at their actual times on the timeline! Is this a bug with the software?
David