Hi RPMDiscs
The WooCommerce variations are a "special" product type that doesn't support any WP taxonomies. Not only ATUM locations but also categories, tags, etc.
Actually, the only way to set locations for variations is by using our Multi-Inventory add-on. With it, you can add one or multiple inventories per product (also per variation) and can link one or multiple locations to each.
Best Regards,
Salva.