Auto populate Start check number against each payment source in Custom Payroll Flow

There is a requirement to Auto populate Start check number against each payment source in Custom Payroll Flow. There are 15 payment sources and I am trying to add generate check payment process 15 times for each payment sources. This custom flow is connected flow of QP with all the required task perform post QP. In the flow the SQL code is not working as expected. I am trying to hard code the payment source value from task parameter. Request your suggestion