Use footers for groups to add summary information for the group, such as totals, subtotals, or average values. To add footer information to a group, create an additional footer for the report.
Any additional footers for a group should typically “break” on the same field as any additional headers for the group. This keeps the headers and footers with the group, and allows the items in the group to be counted.
When you add a field to an additional footer, it is automatically assigned the Last Occurrence display type. If you don’t use the Last Occurrence display type, the field will appear to be looking ahead to the next record for the report. This occurs because the next record for the report has already been read to determine whether a group should be considered complete.
If you place calculated fields in footers, you change their display type from Last Occurrence to Data, so that the calculations are performed properly.