You can change the time increments shown in your Outlook calendar to allow for smaller more detailed calendar entries. This will work in Outlook 2003, Outlook 2007, and Outlook 2010.
There may be times when a number (or result of a calculation) has more than two decimal places. You can tell excel to display only 2 decimal places, but the full number with all the decimal places will be displayed when you click on an individual cell. There is a way to get the worksheet to convert the number to 2 decimal places and round up.