6-608.   Professional services contracts.
   (1)   Contracts for legal services, fiscal agents, auditors, financial advisors or advisory services, educational consultants, engineer consultants, and similar services by professional persons or groups of high ethical standards, shall not be based upon competitive bids, but shall be awarded on the basis of recognized competence and integrity through review of past performance and interviews with prospective contractees, subject to a review of all such contracts by the city's attorney.
   (a)   When written contract required. Except as otherwise provided by this code, and except the services of salaried employees of the city, any services of a professional person or firm, including attorneys, accountants, physicians, architects, and consultants required by the city, whose fee is $2,000.00 or more, shall be evidenced by written contract signed by the person or firm rendering the service and by the city manager after authorization so to do by the city commission; provided, however, that the commission, in its discretion, may contract for such services by the adoption of a written resolution defining the services to be rendered.