I.-The prices of the services covered by a contract are:
1° Either unit prices applied to the quantities actually delivered or performed;
2° Or lump-sum prices applied to all or part of the contract, whatever the quantities delivered or performed.
II.-The National Councils may also conclude contracts at a provisional price. In this case, the clauses of the contracts specify:
1° The conditions under which the definitive price will be determined, within the limit of a ceiling that may be revised;
2° The deadline by which the definitive price must be set;
3° The documentary and on-site checks that the National Council reserves the right to carry out on the technical and accounting elements of the cost price.