Contract number: ECHA/2020/666  II.21.4. Costs of transfer  II.21.5. Pre-financing, performance and money retention guarantees  II.21.6. Interim payments and payment of the balance  40  The contractor (or leader in the case of a joint tender) must send an invoice for interim  payment, as provided for in Article I.6 or in the tender specifications or in the specific  contract. The contracting authority must not request a retention money guarantee for a specific  contract where it has requested a performance guarantee. Retention money guarantees cover full delivery of the service in accordance with the  specific contract including during the contract liability period and until its final approval by  the contracting authority. The retention money guarantee must not exceed 10 % of the  total price of the specific contract. The contracting authority must release the guarantee  after the expiry of the contract liability period as provided for in the specific contract.  Performance guarantees cover compliance with substantial contractual obligations until the  contracting authority has given its final approval for the service. The performance  guarantee must not exceed 10 % of the total price of the specific contract. The contracting  authority must release the guarantee fully after final approval of the service, as provided  for in the specific contract. Pre-financing guarantees must remain in force until the pre-financing is cleared against  interim payments or payment of the balance. Where the payment of the balance takes the  form of a debit note, the pre-financing guarantee must remain in force for three months  after the debit note is sent to the contractor. The contracting authority must release the  guarantee within the following month. The contractor bears the cost of providing such guarantee.  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: The costs of the transfer are borne as follows:  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 (c) the party causing repetition of the transfer bears the costs for repeated transfer.  (b) the contractor bears the costs of receipt charged by its bank;  (a) the contracting authority bears the costs of dispatch charged by its bank;  (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;  (b) the guarantor stands as first-call guarantor and does not require the contracting  authority to have recourse against the principal debtor (the contractor). 