Hi @vverloop!
Automated Taxes is a feature of WooCommerce Services, which is mainly used by US-based stores. The [documentation page](https://docs.woocommerce.com/document/woocommerce-services/#section-7) of the extension already states the following:
__Note: automated tax calculation depends on prices to be entered exclusive of tax._
There are various reasons why this works the way it does, but if your store is based in the Netherlands, I would recommend using a CSV file (like https://www.wpdesk.net/blog/woocommerce-eu-vat-csv/) and importing it. Taxes in the EU are much simpler than those in the US, and since you should not be collecting taxes for US sales (correct me if I am wrong), WooCommerce Services is an overkill for you.