What do the fields in the Estimates and Actuals sections of the Edit Project page represent?

Following is a description of each of these fields.

In the Estimates section

1. The Task Hours field is a computed field and shows the sum of the estimated hours on each task in the project.
2. You may also provide a value for the Project Hours field for whatever time you believe will be required that is not directly related to one specific task in the project.
3. The Total Hours field is a computed field and shows the sum of items 1 and 2 above.

In the Actuals section

1. The Task Hours field is a computed field which shows the total actual hours that users recorded in their timesheets against tasks in the project.
2. The Project Hours field is a computed field which shows the total actual hours that users recorded in their timesheets against the project without specifying a task. When a user enters time using the “manual” mode (as opposed to the Timeclock mode), it is possible to leave the task field blank in which case the hours are recorded as project hours.
3. The Total Hours field is a computed field and shows the sum of items 1 and 2 above.