Out of the box Acumatica allows to create and maintain the list of shipping terms in the system. Shipping terms are used to define the shipping, packaging and handling costs, depending on the shipment amount.

In this example I will show how to calculate freight amount for a shipment based on sales order amount, which would allow users to create multiple shipments per sales order with same shipping terms automatically applied to all shipments.

FreightCalculator

The FreightCalculator class is responsible for calculation of Freight Cost and Freight Terms. For the purpose of this example, our interest will be only around the GetFreightTerms method:

public class FreightCalculator
{
    ...

    protected virtual ShipTermsDetail GetFreightTerms(string shipTermsID, decimal? lineTotal)
    {
        return PXSelect<ShipTermsDetail,
            Where<ShipTermsDetail.shipTermsID, Equal<Required<SOOrder.shipTermsID>>,
            And<ShipTermsDetail.breakAmount, LessEqual<Required<SOOrder.lineTotal>>>>,
            OrderBy<Desc<ShipTermsDetail.breakAmount>>>.Select(graph, shipTermsID, lineTotal);
    }

    ...
}

Both the Sales Orders and the Shipments screens utilize FreightCalculator class to calculate freight amount based on sales order's and shipment's amount respectively:

Sales Orders

public class SOOrderEntry : PXGraph<SOOrderEntry, SOOrder>, PXImportAttribute.IPXPrepareItems
{
    ...

    public virtual FreightCalculator CreateFreightCalculator()
    {
        return new FreightCalculator(this);
    }

    ...

    protected virtual void SOOrder_RowUpdated(PXCache sender, PXRowUpdatedEventArgs e)
    {
        ...

        PXResultset<SOLine> res = Transactions.Select();
        FreightCalculator fc = CreateFreightCalculator();
        fc.CalcFreight<SOOrder, SOOrder.curyFreightCost, SOOrder.curyFreightAmt>(sender, (SOOrder)e.Row, res.Count);

        ...
    }

    ...
}

Shipments

public class SOShipmentEntry : PXGraph<SOShipmentEntry, SOShipment>
{
    ...

    protected virtual FreightCalculator CreateFreightCalculator()
    {
        return new FreightCalculator(this);
    }

    ...

    protected virtual void SOShipment_RowUpdated(PXCache sender, PXRowUpdatedEventArgs e)
    {
        ...

        PXResultset<SOShipLine> res = Transactions.Select();
        ...
        FreightCalculator fc = CreateFreightCalculator();
        fc.CalcFreight<SOShipment, SOShipment.curyFreightCost, SOShipment.curyFreightAmt>(sender, (SOShipment)e.Row, res.Count);

        ...
    }

    ...
}

Overriding Freight Amount

To customize how Acumatica calculates freight amount on the Shipments screen I will declare FreightCalculatorCst class inherited from FreightCalculator and override GetFreightTerms method:

public class FreightCalculatorCst : FreightCalculator
{
    public FreightCalculatorCst(PXGraph graph)
        : base(graph)
    {
    }

    protected override ShipTermsDetail GetFreightTerms(string shipTermsID, decimal? lineTotal)
    {
        if (graph is SOShipmentEntry)
        {
            var shipmentEntry = graph as SOShipmentEntry;
            int orderCount = 0;
            decimal? lineTotalTemp = null;

            foreach (PXResult<SOOrderShipment, SOOrder, CurrencyInfo, SOAddress, SOContact, SOOrderType> orderRec in 
                shipmentEntry.OrderList.SelectWindowed(0, 2))
            {
                orderCount++;
                SOOrder order = (SOOrder)orderRec;
                if (orderCount == 1)
                    lineTotalTemp = order.LineTotal;
                else
                    break;
            }

            if (orderCount == 1)
            {
                lineTotal = lineTotalTemp;
            }
        }

        return base.GetFreightTerms(shipTermsID, lineTotal);
    }
}

After that I will implement an extension for the SOShipmentEntry BLC and override CreateFreightCalculator method to replace FreightCalculator with my custom FreightCalculatorCst class on the Shipments screen:

public class SOShipmentEntryExt : PXGraphExtension<SOShipmentEntry>
{
    [PXOverride]
    public FreightCalculator CreateFreightCalculator()
    {
        return new FreightCalculatorCst(Base);
    }
}

Understanding implementation of the FreightCalculatorCst class in the sample above

In the overridden GetFreightTerms method I will use amount from sales order instead of shipment amount to invoke base GetFreightTerms method and receive shipping terms:

foreach (PXResult<SOOrderShipment, SOOrder, CurrencyInfo, SOAddress, SOContact, SOOrderType> orderRec in 
    shipmentEntry.OrderList.SelectWindowed(0, 2))
{
    orderCount++;
    SOOrder order = (SOOrder)orderRec;
    if (orderCount == 1)
        lineTotalTemp = order.LineTotal;
    else
        break;
}

if (orderCount == 1)
{
    lineTotal = lineTotalTemp;
}

Obviously, it's only possible to use sales order amount to calculate freight amount for shipments, which fulfill only 1 order. If one shipment fulfills several orders, we'd have to follow base product behavior and calculate freight amount based on shipment amount. To check the number of orders shipment fulfills, I used SelectWindowed method on the OrderList data view and requested first 2 orders fulfilled by the current shipment. I could have requested all orders fulfilled by the shipment, but this would take significantly more time to execute and return way to many records than needed to verify if sales order amount can be used instead of shipment amount to calculate freight.