code: public Number getOvertimeCost()
     {
        Number cost = (Number) getCachedValue(AssignmentField.OVERTIME_COST);
        if (cost == null)
        {
           Number actual = getActualOvertimeCost();
           Number remaining = getRemainingOvertimeCost();
           if (actual != null && remaining != null)
           {
              cost = NumberHelper.getDouble(actual.doubleValue() + remaining.doubleValue());
              set(AssignmentField.OVERTIME_COST, cost);
           }
        }
        return (cost);
     }
docs: Returns the overtime cost of this resource assignment.
  
  @return cost