Amount In Words In Crystal Report

uppercase(ToWords (Sum ({command.NetValue},{command.InvoiceNo}),0) + " and cents "+ ToWords ((Round(Sum ({command.NetValue}, {command.InvoiceNo}),2)
- Int(Sum ({command.NetValue}, {command.InvoiceNo}))) * 100, 0) + " Only")

The above is my code, its working fine. but the value is getting double due to sum of in the field. I need to remove the sum of in the above formula.