- check the reported discrepancy in gross, vat, zero vat, and global disc columns in per counter summary report
- as per checking the script is not including in the filter some operation type to thus it returns an incorrect value
- modify the script and add the operation type group and check the script if the data will now return a correct value
apply the modified script in the report and check again the output, as the data is now ok. 
- double-check the data for a summary of the discount report, there is no value in discount type and employee name column
- as per checking the ticket number from valid tickets for the discount transaction has no equivalent data in customer table causing of no data for name to return