Use of EvSUB

I came across the EvSUB function while researching a solution to a problem I was having trying to include sub-totals and totals in one single report.  I tried using the function in a report and could not get it to work when expanding.  Can someone shed some on this function or provide an example of how it can be used.

http://help.sap.com/saphelp_bpc70sp02/helpdata/en/b2/f117dd464b4252a279ab7f67b4436d/content.htm

We are running MS 7.5 SP4 I believe.