Although the OSS was designed to simplify and streamline VAT remittances, the complexity of the new EU VAT rules creates a myriad of tax compliance challenges and requires companies to think carefully about their operations and how they implement digital tax reporting. For instance:   Each of the 27 EU member states may have different VAT rates for the same goods or services supplied Reporting processes and digital filing formats are not standardized throughout the EU — some countries insist on CSV documents, while others require XML submissions Non-EU established online sellers may require assistance from a fiscal representative to act on their behalf in the member state of IOSS or Non-Union OSS registration