Store API: Recommendation for additional address fields

Hi,

are there recommendations on how to get additional address fields (like VAT) into the WooCommerce Store API address schemas? Do I have to use the ExtendSchema like mentioned in https://github.com/woocommerce/woocommerce-blocks/tree/trunk/src/StoreApi#extensibility

I need to use the API for a custom checkout process and have additional address fields like VAT Code – added by the Germanized WooCommerce plugin – which my customers also must provide.