Did you use Tasks >  "Enter Time" for each employee? If the rate column appears on your Time Entry View you should have seen the rates appear after each line of time was entered. You didn't mention Enter Time, only Process Payroll.  Process Payroll without time entry only works for salaried employees where their pay is marked "Auto". 

If your rate retrieval was previously working, and you sure that you changed only the amount on your existing rate tables for the correct unions, union local and union class?

Art Minds

Independent Senior-level Consultant

Process payroll is not going to change the rate associated with any time entries where the rate was retrieved from a Rate Table that were recorded prior to making the change to the Rate Table.