submitted with the interim progress reports; and 

(b) the amounts claimed as incidental expenditure have actually and necessarily been incurred by the Consultant in accordance with the requirements of the terms of reference of the contract. 

(c) On the basis of his/her verification, the auditor submits to the Consultant an expenditure verification report in accordance with the model in Annex VII. . 

28.4. The Consultant grants the auditor all access rights mentioned in Article 25. 

28.5. The Contracting Authority reserves the right to require that the auditor be replaced if considerations which were unknown when the Contract was signed cast doubt on the auditor's independence or professional standards. 

## ARTICLE 29. PAYMENT AND INTEREST ON LATE PAYMENT 

29.1. Payments will be made in accordance with one of the two options below, as identified in Article 3 of the Special Conditions. 

## Option 1: Fee-based contract 

The Contracting Authority will make payments to the Consultant in the following manner: 

1. A pre-financing payment, if requested by the Consultant, of an amount as requested up to the maximum specified below, within 45 days of receipt by the Contracting Authority of the Contract signed by both parties, of a request for payment and of a financial guarantee, as defined in Article 30. The pre-financing shall be of a maximum of 30 % of the total contract amount if the implementation period of the tasks is 24 months or less, and 20 % of the total contract amount if the implementation period of the tasks is more than 24 months. 

2. Six-monthly interim payments, if any, as indicated in Article 7.2 of the Special Conditions, within 45 days of the Contracting Authority approving an interim progress report and an expenditure verification report accompanied by an invoice, in accordance with Article 27. Such interim payments shall be of an amount equivalent to the costs incurred on the basis of the expenditure verification reports. When 80% of the contract amount has been paid (pre-financing and interim payments) the amounts due to the Consultant shall be deducted from the pre-financing payment until it is completely reimbursed before any additional payments will be made. 

3. The invoices must be paid such that the sum of payments does not exceed 90% of the maximum contract value stated in Article 3 of the Special Conditions; the 10% being the minimum final payment. 

4. The balance of the final value of the contract after verification, subject to the maximum contract value stated in Article 3 of the Special Conditions, after deduction of the amounts already paid, within 45 days of the Contracting Authority receiving an invoice accompanied by the final progress report and a final expenditure verification report subject to approval of those reports in accordance with Article 27. 

## Option 2: Global price contract 

The Contracting Authority will make payments to the Consultant in the following manner: 

1. a pre-financing payment up to 30 % of the contract value stated in Article 3 of the Special Conditions within 45 days of receipt by the Contracting Authority of the Contract signed by both parties, and of a financial guarantee, as defined in Article 30; 

2. the balance of the contract value stated in Article 3 of the Special Conditions within 45 days of the Contracting Authority receiving a final invoice accompanied by the final progress report, subject to approval of that report in accordance with Article 27 

29.2. The payment deadline of 45 calendar days referred to in Article 29.1 shall expire on the date on which the Contracting Authority’s account is debited. Without prejudice to Article 36.3, the Contracting Authority may halt the countdown towards this deadline for any part of the invoiced amount disputed by the Project Manager by notifying the Consultant that part of the invoice is inadmissible, either because the amount in question is not due or because the relevant report cannot be approved and the Contracting Authority thinks it necessary to conduct further checks. In such cases, the Contracting Authority must not unreasonably withhold any undisputed part of the invoiced amount but may request clarification, alteration or additional information, which must be produced within 30 days of the request. The countdown towards the deadline will resume on the date on which a correctly formulated invoice 

