Contract number: [ complete ]  Service contract conditions of December 2018  Reception of invoices by standard format (pdf) or email is not accepted. If a price revision index is provided in Article I.4.2, this Article applies to it. Prices are fixed and not subject to revision during the first year of the contract.  At the beginning of the second and every following year of the contract, 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 contract. 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 price revision is calculated using the following formula:  The date of payment is deemed to be the date on which the contracting authority's account is  debited.  Payments are made in euros, unless another currency is provided for in Article I.7. The contracting authority makes any conversion between the euro and another currency at the  daily euro exchange rate published in the Official Journal of the European Union, or failing  that, at the monthly accounting exchange rate, as established by the European Commission  and published on the website indicated below, applicable on the day when it issues the  payment order. The contractor makes any conversion between the euro and another currency at the monthly  accounting exchange rate, established by the Commission and published on the website  indicated below, applicable on the date of the invoice.  http://ec.europa.eu/budget/contracts_grants/info_contracts/inforeuro/inforeuro_en.cfm II.21.2. Currency  II.21.1. Date of payment  II.21. PAYMENTS AND GUARANTEES  II.21.3. Conversion  II.20. PRICE REVISION  where:  33  Pr = revised price;  Po = price in the tender;  Io = index for the month in which the contract enters into force;  Ir = index for the month in which the request to revise prices is received.  Ir  Pr = Po x ( — )  Io 