This is a kind of combination of Row and column report and Summation report. Get detailed data, grouped, sorted according to your requirement, add to it summation information.
This is one of most comprehensive reports in SugarCRM, We can get almost any kind of report with this type. But don't be tempted to use this always, it would be a overkill with all its power. You don't need all those options and choices always.
In this video, we explain the need with examples and then demonstrate how to create Summation reports. After that we try different permutations and combinations . This is just the beginning, try out different variants on your own.