Tax Class isn’t applied

I’ve created a number input with a dynamic price. It should be taxable, but not use the standard VAT (19%) but a temporarily reduced VAT (16%). I’ve created an extra tax class for the 16% and applied it in the field settings in the Checkout Field Editor.

The Problem: In the overview at the end of the checkout process, it always lists “inkl. 19% VAT” for the field in question, no matter what tax class i put in the checkout field settings or what tax class any of the products might have.

I’m using the tax class i created for some of the products without any problems, so there shouldn’t be any issues with the tax class itself.

Have you encountered this problem before? How do i fix this?