The reports that are built in are almost always impossible to use for any kind of data/filtering/analysis purpose because they don't obey the simple structure of an excel table (rows and columns) when exported in Excel format. Instead they export in a "printable" format that tries to be a Word document or PDF in Excel. We currently have to rebuild all of these reports with advanced lists in order to get the data in a usable format.
e.g. student conflict report
The main reason for exporting to Excel in the first place is to do just this kind of data/filtering/analysis. If you insist on exporting Excel in report format, then provide a 'Data Only' style export that gives what is described above.