How can we effectively test VAT and currency changes on Shopify?

Hi all,

We are having problems figuring out how to test the changing prices within a Shopify environment based on the location of the customer.

Before the new VAT system we used to have our own front-end based code which deducted the shops main VAT from the price to show beneath the default price. This was a solution once suggested by Shopify but it’s an old one. See it like

{{ product.price | times: tax_modifier }}

The merchant sent us a screenshot where he says: An American customer placed an order where the front-end didn’t match up with the prices in the checkout. This was due to the VAT already being deducted from the product.price object. So our front-end calculation is double and not needed.

But when we visit the website with Hola or some other proxy. The VAT is not deducted from the price object and our front-end filter just works as we want to.

Does someone have a clue on how we can properly test this?

For reference. The Ex 21% vat btw is what we have added with our own front-end calculation.