This report works based on how the Contract Rate is loaded against the customer.
Running the report with no Parameters will display all Contract Rates
To report on individual product rates, enter the code in both sides code field. If the ZZZZ's are not removed from the Product Group Rates - Group these will show as well.
To filter only by those Contract Rates applied to specific groups, enter in the Group in both fields and remove the ZZZZZ's from the product code.