Why count on chart is different than count on table?

Question

On a report "Summation with details", I get two different values on the bar chart and on the table underneath the chart. 
 
 Isn't it misleading? 
 Thanks

Omar Conte · Answer

Hi Omar, 
 One additional possibility is that your report details are returning the same record multiple times. This can happen if you are including a display field or filter condition from a related module that has a many-to-one or many-to-many relationship with your primary module. In those instances, a row will show in the report for each related record. However, the chart in the report only shows a unique count of records for each grouping. 
 Chris