Hi there,

The Shipping Tax should only apply for the Billing Address and it doesn't have to change even if the user inputs a different Shipping Address.

I see that now when a user buys a product and he fills the Billing Address, when he fills the Shipping Address if this is different for the billing address, the TAX also changes depending the Shipping country or zip code.

This shouldn't happen, it only needs to change the Shipping Costs and not the TAX, as the TAX it is always for the BILLING ADDRESS needed for the INVOICE BILL and has to be the same as the one inserted in the BILLING ADDRESS