If you were among the customers using the Multiple VAT Registrations module (meaning you were registered for VAT in another country) or need to use this module simultaneously with the OSS scheme, it is necessary to distinguish between these two schemes on invoices.
If you were using multiple VAT registrations up to 30 June 2021 and switched to the OSS scheme from 1 July 2021, simply create a new document type for OSS, which you will use for the relevant documents. In the menu Tools - Codebooks - Countries, you can then delete the VAT ID for the specific country (or countries) — however, do this only once you are certain that you will not be adding any historical documents dated before 30 June 2021.
When combining these schemes, Flexi follows the accounting template assigned to the document. If the document contains an accounting template with a VAT fulfillment code for OSS, that invoice will appear in the OSS return. If any other accounting template is used and the VAT country is other than the Czech Republic, Flexi behaves in the standard way as in the original Multiple VAT Registrations module.
It is therefore important to have a dedicated document type for OSS, where the accounting template is filled in with the fulfillment code for OSS, and a separate document type for multiple VAT registrations, where a standard accounting template will be used.
Note: When importing an OSS invoice in combination with a VAT registration, the correct VAT line must be corrected retroactively using a bulk change.