26.5. The payments shall be made as follows: 

a) 40% of the total contract price after the signing of the contract, against provision of the performance guarantee and of a pre-financing guarantee for the full amount of the pre-financing payment, unless otherwise provided for in the special conditions. The pre-financing guarantee shall be provided to the contracting authority following the procedure foreseen for the performance guarantee in accordance with Article 11.3-5, and in accordance with the format annexed to the contract. The pre-financing guarantee must remain valid until it is released 30 days at the latest after the provisional acceptance of the goods. Where the contractor is a public body, the obligation for a pre-financing guarantee may be waived depending on a risk assessment made; 

b) 60% of the total contract price, as payment of the balance, after receipt by the contracting authority of an invoice and of the application for the certificate of provisional acceptance; 

26.6. Where only part of the supplies has been delivered, the 60% payment due following partial provisional acceptance shall be calculated on the value of the supplies which have actually been accepted and the security shall be released accordingly. 

26.7. For supplies not covered by a warranty period, the payments listed above shall be aggregated. The conditions to which the payments of pre-financing and final payments are subject, shall be as stated in the special conditions. 

26.8. The payment obligations of the European Commission under this contract shall cease at most 18 months after the end of the period of implementation of the tasks, unless the contract is terminated in accordance with these general conditions. 

26.9. Unless otherwise stipulated in the special conditions, the contract shall be at fixed prices, which shall not be revised. 

26.10. The contractor undertakes to repay any amounts paid in excess of the final amount due to the contracting authority before the deadline indicated in the debit note which is 45 days from the issuing of that note. Should the contractor fail to make repayment within the above deadline, the contracting authority may (unless the contractor is a government department or public body of a Member State of the European Union) increase the amounts due by adding interest: 

 at the rediscount rate applied by the central bank of the country of the contracting authority if payments are in the currency of that country; 

 at the rate applied by the European Central Bank to its main refinancing transactions in euro, as published in the Official Journal of the European Union, C series, where payments are in euro, 

on the first day of the month in which the time-limit expired, plus eight percentage points. The default interest shall be incurred over the time which elapses between the date of the payment deadline, and the date on which payment is actually made. Any partial payments shall first cover the interest thus established. 

Amounts to be repaid to the contracting authority may be offset against amounts of any kind due to the contractor. This shall not affect the parties' right to agree on payment in instalments. Bank charges arising from the repayment of amounts due to the contracting authority shall be borne entirely by the contractor. 

