Field help (RECCUMCAL) 

If the total is populated by a new heading, a recalculation of the total with a payroll recalculation must be launched. The recalculation of the payroll does not modify the payslip.
If the "Payroll recalculation" option is not selected, the total is calculated according to the setup defining the transfer of the headings into the total. The amount of each heading is not recalculated.