Hi EquineAmericaNZ
OK, let me explain it again.
If you enable Multi-Inventory for any product, that meta box you mentioned in your previous post (the one shown in the screenshot you attached) is not available. That meta box is only for products with Multi-Inventory disabled.
When Multi-Inventory is enabled for any product, the locations must be set per inventory (and not per product). So you have to click the marker icon on the inventory data section (https://stockmanagementlabs.crunch.help/en/atum-multi-inventory/the-multi-inventory-data-fields) and assign them from it to every inventory.
I hope it's more clear now 🙂
Best Regards,
Salva.