// check kolom SO
                        _shipping.PriceNullAble = 0;

                        var SW = refund.FPPBHeader.SalesOrder.ShippingCostWarehouse;
                        var SS = refund.FPPBHeader.SalesOrder.ShippingCostSupplier;
                        var SB = refund.FPPBHeader.SalesOrder.ShippingCostBookingDirect;
                        var SD = string.IsNullOrEmpty(refund.FPPBHeader.SalesOrder.ShippingCostDiscount.ToString()) ? 0 : refund.FPPBHeader.SalesOrder.ShippingCostDiscount;

                        if (!string.IsNullOrEmpty(SW.ToString())
                            && string.IsNullOrEmpty(SS.ToString())
                            && string.IsNullOrEmpty(SB.ToString()))
                        {
                            _shipping.PriceNullAble = SW - SD;
                        }
                        else if (string.IsNullOrEmpty(SW.ToString())
                           && !string.IsNullOrEmpty(SS.ToString())
                           && string.IsNullOrEmpty(SB.ToString()))
                        {

                            _shipping.PriceNullAble = SS - SD;

                        }
                        else if (string.IsNullOrEmpty(SW.ToString())
                           && string.IsNullOrEmpty(SS.ToString())
                           && !string.IsNullOrEmpty(SB.ToString()))
                        {

                            _shipping.PriceNullAble = SS;

                        }
                        else if (!string.IsNullOrEmpty(SW.ToString())
                           && !string.IsNullOrEmpty(SS.ToString())
                           && string.IsNullOrEmpty(SB.ToString()))
                        {

                            _shipping.PriceNullAble = (SW + SS) - SD;

                        }
                        else if (!string.IsNullOrEmpty(SW.ToString())
                           && string.IsNullOrEmpty(SS.ToString())
                           && !string.IsNullOrEmpty(SB.ToString()))
                        {

                            _shipping.PriceNullAble = (SW - SD) + SB;

                        }
                        else if (string.IsNullOrEmpty(SW.ToString())
                           && !string.IsNullOrEmpty(SS.ToString())
                           && !string.IsNullOrEmpty(SB.ToString()))
                        {

                            _shipping.PriceNullAble = (SS - SD) + SB;

                        }
                        else if (!string.IsNullOrEmpty(SW.ToString())
                           && !string.IsNullOrEmpty(SS.ToString())
                           && !string.IsNullOrEmpty(SB.ToString()))
                        {

                            _shipping.PriceNullAble = ((SW + SS) - SD) + SB;

                        }

                        _shipping.Price = _shipping.PriceNullAble.GetValueOrDefault(0);