This report shows the total hours worked, number of days present and the average hours per day for any month. This report can be generated for one month for all employees.
Details of columns are -
 1. Official Hours - this field is calculated based on the setup done on Attendance
  Setup page in "Official Hours / Days Worked Definition" table. If Shift Begin
  and Shift End times are selected in setup as the basis for Official Hours then
  total number of hours in the shift are taken, breaks are not excluded.
 2. Shift Hours - If a particular day is counted as "Days Worked" as per Attendance
  Setup then Shift hours for that day are also counted.  For days when the
  attendance status is a mix of two or more status the hours will be calculated
  only if Multiple Status column is selected.
 For example if a company has 9 am to 6 pm shift and an employee is on half day
  leave and is present for half day and Multiple Status box is selected for "Days
  Worked" then the Shift Hours will be equal to 9 hours. If the box is not selected
  then Shift Hours will be zero.
 3. Days Worked - this field is calculated based on the setup done on Attendance
  Setup page in "Official Hours / Days Worked Definition" table
 4. Avg Hrs/Day - formula is- Official Hours / Days Worked
In the detailed excel which you can get by clicking on "Export All Details" button
  you will see the following additional details -
 1.  Official Hours for each day will be shown separately
 2. Shortfall hours - total of shortfall hours will be shown, shortfall is calculated
  as follows - If employee has worked less then his shift hours then it will count
  as shortfall, "Shortfall = Actual Shift Hours - Actual Hours Worked", this column
  will show sum of shortfall hours for all days in the range
 3. Extra hours - total of extra hours if worked will be shown, extra hours are
  calculated as follows - If employee has worked more then his shift hours then
  the extra hours will be calculated,  "Extra Hours = Actual Hours Worked
  - Actual Shift Hours", this column will show sum of extra hrs for all days
Sample reports are available in article attachments.