I have read the thread, and checked that my settings are correct: System> Configuration> Sales> Delivery Settings> Origin = Spain
I think that if invoices are calculated correctly, the problem is just the way like Magento processes the orders.
Prices were introduced in the Back-end excluding VAT, although in the catalog (front-end) prices are shown correctly because they include VAT
The situation is (attached a picture for better comprehension)
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