Although Social looks for latitude/longitude tags and location data in users' Twitter bios, geo-data is available for only 5 to 30 percent of all tweets. As a result, you should not expect the total number of tweets for a display name to equal the total sum of all reported geographic locations. You can click Details in each tweet in the Posts reportlet to see the geo-location Social ascribes to each mention. If Social cannot determine the location, the location is not available.