The field Premium that appears on a report represents the hours equal to the difference between the overtime hours physically worked and the overtime hours paid. These premium hours are not added to your grand totals but can be used for reporting production costs.
For example, an employee works two hours overtime, calculated as time and a half, so is paid for three normal working hours.
The Actual overtime the employee physically worked is two hours.
The Paid overtime is three hours.
The Premium overtime is therefore one hour that the employee didn't physically work but was paid for.