25.4. If the project manager is not present on the date agreed for tests, the contractor may,  unless otherwise instructed by the project manager, proceed with the tests, which shall be  deemed to have been made in the project manager's presence. The contractor shall  immediately send duly certified copies of the test results to the project manager, who  shall, if it has not attended the test, be bound by the test results.  25.5. When components and materials have passed the above-mentioned tests, the project  manager shall notify the contractor or endorse the contractor's certificate to that effect.  25.6. If the project manager and the contractor disagree on the test results, each shall give a  statement of its views to the other within 15 days of such disagreement arises. The project  manager or the contractor may require such tests to be repeated on the same terms and  conditions or, if either party so requests, by an expert selected by common consent. All  test reports shall be submitted to the project manager, who shall communicate the results  of these tests without delay to the contractor. The results of retesting shall be conclusive.  The cost of retesting shall be borne by the party whose views are proved wrong by the  retesting.  25.7. In the performance of their duties, the project manager and any person authorised by him  shall not disclose to unauthorised persons information concerning the undertaking's  methods of manufacture and operation obtained through inspection and testing.  26.1. Payments shall be made in euro or national currency as specified in the special  conditions. The special conditions shall lay down the administrative or technical  conditions governing payments of pre-financing and final payments made in accordance  with the general conditions. 26.2. Payments due by the contracting authority shall be made to the bank account mentioned  on the financial identification form completed by the contractor. The same form, annexed  to the invoice, must be used to report changes of bank account.  26.3. Pre-financing payment shall be made within 30 days from the date on which an  admissible invoice is registered by the contracting authority. The invoice shall not be  admissible if one or more essential requirements are not met. Final payment shall be  made within 60 days from the date on which an invoice is registered by the contracting  authority, together with the request for provisional acceptance as per article 31.2. The  date of payment shall be the date on which the paying account is debited. 26.4. The period referred to in article 26.3 may be suspended by notifying the contractor that  the invoice cannot be fulfilled because the sum is not due, because appropriate  substantiating documents have not been provided or because there is evidence that the  expenditure might not be eligible. In the latter case, an inspection may be carried out on  the spot for the purpose of further checks. The contractor shall provide clarifications,  modifications or further information within 30 days of being asked to do so. The payment  period shall continue to run from the date on which a properly drawn-up invoice is  registered.  August 2020 c4e_annexigc_en  Page 21 of 36  PAYMENTS  Article 26 -  General principles 