Contract number: EEAS-618-DELBRBB-SER-FWC-2019   Template of June 2018 Updated November 2018  The contractor (or leader in the case of a joint tender) must complete the necessary formalities  with the relevant authorities to ensure that the supplies and services required for  implementation of the FWC  are exempt from taxes and duties, including VAT.  If provided for in the special conditions, the contractor (or leader in the case of a joint tender)  submits invoices in electronic format if the conditions regarding electronic signature specified  by Directive 2006/112/EC on VAT are fulfilled, i.e. using a qualified electronic signature or  through electronic data interchange. Reception of invoices by standard format (pdf) or email is not accepted. If a price revision index is provided in Article I.5.2, this Article applies to it. Prices are fixed and not subject to revision during the first year of the FWC.  At the beginning of the second and every following year of the FWC, each price may be  revised upwards or downwards at the request of one of the parties.  A party may request a price revision in writing no later than three months before the  anniversary date of entry into force of the FWC. The other party must acknowledge the  request within 14 days of receipt. At the anniversary date, the contracting authority must communicate the final index for the  month in which the request was received, or failing that, the last provisional index available  for that month. The contractor establishes the new price on this basis and communicates it as  soon as possible to the contracting authority for verification. The contracting authority purchases on the basis of the prices in force at the date on which the  specific contract enters into force.  The price revision is calculated using the following formula:  Ir  Pr = Po x ( — )  Io  where:  Pr = revised price;  Po = price in the tender;  Io = index for the month in which the FWC enters into force;  Ir = index for the month in which the request to revise prices is received. 32  II.20. PRICE REVISION  II.19.2. E-invoicing 