Forecast quantity (computed as Quantity On Hand - Outgoing + Incoming)
In a context with a single Stock Location, this includes goods stored at this Location, or any of its children.
In a context with a single Warehouse, this includes goods stored in the Stock Location of this Warehouse, or any of its children.
In a context with a single Shop, this includes goods stored in the Stock Location of the Warehouse of this Shop, or any of its children.
Otherwise, this includes goods stored in any Stock Location typed as 'internal'.