How does location assignment hierarchy work for order shipments?

[Gemini_II]

Hello!

I have 5 locations including one default 'Unassigned' location where orders are assigned the other locations for shipment.   However, some orders are coming through automatically assigned to a location other than the default location.   Is there a hierarchy that Shopify uses when assigning to a location other than the default.   For example, if the item is not stocked at the default location, does it automatically assign to the location with the most SOH?   I am trying to keep orders from being assigned to other locations until I have manually changed the location from the default.