I too a look at the sample report pack from SAP and I noticed that when they created a graph (even over expanding groups), they were selecting the cell below the value as well.
When I first added the graph to the report, I selected the expanding row value (e.g., $B$6) only as the data values for the graph and ran the report. The graph only displayed one value, the first line of the expanding row. A little frustrated, I took a look at one of their examples and found that they were selecting the cell right below the expanding row as well (e.g., $B$6 and $B$7, written in Excel as $B$6:$B$7). This produced the results that I was expecting. I did the same thing for the value labels for the graph (e.g., $A$6:$A$7).
Thanks to Ed Monk of SBONotes.com