Amazon MWS - Update inventory Separation of MFN and AFN when updating stock

Question

I am updating stock by updating Amazon MWS service. I only want to update the MFN stock quantity while updating the stock. I have MFN and AFN product with same SKU value.

https://images-na.ssl-images-amazon.com/images/G/01/rainier/help/xsd/release_4_1/Inventory.xsd

When I want to update the stock with the parameters in the link, AFN also updates the stock level. How can I update only MFN stocks?

Answer 1

Odd. From this document (and you may need to be logged into the seller account), they say that to update MFN inventory, send this (p43):

<AmazonEnvelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="amzn-envelope.xsd">
    <Header>
        <DocumentVersion>1.01</DocumentVersion>
        <MerchantIdentifier>M_tokenhere_12345</MerchantIdentifier>
    </Header>
    <MessageType>Inventory</MessageType>
    <Message>
        <MessageID>1</MessageID>
        <OperationType>Update</OperationType>
        <Inventory>
            <SKU>12345</SKU>
            <FulfillmentCenterID>DEFAULT</FulfillmentCenterID>
            <Quantity>1</Quantity>
            <SwitchFulfillmentTo>MFN</SwitchFulfillmentTo>
        </Inventory>
    </Message>
</AmazonEnvelope>

else for AFN / FBA send this:

<?xml version="1.0" encoding="UTF-8"?>
<AmazonEnvelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="amzn-envelope.xsd">
    <Header>
        <DocumentVersion>1.01</DocumentVersion>
        <MerchantIdentifier>M_tokenhere_12345</MerchantIdentifier>
    </Header>
    <MessageType>Inventory</MessageType>
    <Message>
        <MessageID>1</MessageID>
        <OperationType>Update</OperationType>
        <Inventory>
            <SKU>2000578900007</SKU>
            <FulfillmentCenterID>AMAZON_NA</FulfillmentCenterID>
            <Lookup>FulfillmentNetwork</Lookup>
            <SwitchFulfillmentTo>AFN</SwitchFulfillmentTo>
        </Inventory>
    </Message>
</AmazonEnvelope>

ie AFN/FBA stock is maintained by Amazon whilst for MFN we're responsible for.