Contract number: [ complete ]  Service contract conditions of December 2018  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.  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 The costs of the transfer are borne as follows:  If, as provided for in Article I.6 , a financial guarantee is required for the payment of pre- financing, as performance guarantee or as retention money guarantee, it must fulfil the  following conditions: PAYMENTS AND GUARANTEES  II.21. Date of payment  II.21.1. Currency  II.21.2. Conversion  II.21.3. Costs of transfer  II.21.4. Pre-financing, performance and money retention guarantees  II.21.5. (a) the financial guarantee is provided by a bank or a financial institution approved by the  contracting authority or, at the request of the contractor and with the agreement of the  contracting authority, by a third party; and  (b) the guarantee shall have the effect of making the bank or financial institution or the  third party provide irrevocable collateral security, or stand as first-call guarantor of the  contractor's obligations without requiring that the contracting authority has recourse  against the principal debtor (the contractor).  (a) the contracting authority bears the costs of dispatch charged by its bank;  (b) the contractor bears the costs of receipt charged by its bank;  (c) the party causing repetition of the transfer bears the costs for repeated transfer.  33 