A Break Total is a user-enabled Pivot section row that can display summarized Fact information at the change of a level of Row Label information.
For example, in the above Pivot section, to see the sum of Unit Sales for all Cities, add a "Sum" Break Total line at the end of the City Row Label level as shown below:
If you intend to use Break Totals in your Pivot section, be sure to enable surface values instead of using the underlying table data. In this way, Break Totals reflects the aggregation of displayed detail data.
If you use the “Add Totals” menu option to add a Break Total, the Break Total preserves any data function applied to a Fact Column.