In which scenarios should the Magento module pass the `StoreID` parameter to AlphaCommerceHub?

The StoreID request parameter is marked as optional in the «API Integration Guide(Nov 2017)» → «API Reference» → «Request Message» documentation section, so I do not understand when the Magento module should or should not pass it to AlphaCommerceHub:

Parameter Name Type Format Mandatory Description
StoreID Alpha O Store ID assigned by APC (primarily used in card present transactions)

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I have got a response from AlphaCommerceHub:

RG: Not foreseen at present.
This is another hierarchy level below the merchant which is not presently used