The Update Service Item Totals utility will read through the service history and recalculate the totals for each service item. These totals include:
TotalWarrantyHours
TotalWarrantyLaborCost
TotalBillableHours
TotalServiceLaborCost
TotalServiceLaborSales
TotalServiceMaterialCost
TotalWarrantyMaterialCost
TotalMaterialSales
The primary reason for running this utility is when you have upgraded from a legacy version of Service Center (Service & Warranty Management) which did not maintain these totals. It does not do any damage to run it again if you are not sure.