In order to track how many selling stations were active in a month, build the following report.
Go to "Reporting" in the top navigation menu, then "Analysis"
Filter the date to view "last month" (or your exact billing dates if they differ from last month)
Location >> Name
Sales Transaction >> Station
"Location sales >> Gross sales" (Remember to use "Location sales" rather than "Source Sales" to track sales from each station)
This metric shows you exactly how many selling stations were used during a period and gross sales dollars per selling station.