Click on the Prefs icon above (try it now) to select your TimeTracker preferences.
 
The Default Settings apply to new documents (documents created when you select New from the File menu). For example, if you wanted all new documents to automatically save to disk every five minutes, you would click on “Always set new files to Auto-Save.” The Auto-Save minutes can have a value from 1 to 60 minutes.
The Time Display for all documents is set here. The actual time entry is not altered, but rounded up to the nearest increment. For example, if you set the preferences to use 6 minute increments, and you work for 13 minutes, the time entry displays 18 minutes.
Decimal notation is only available for increments above 1 minute.