Vacancies in positions above the entrance level shall be filled by promotion whenever in the judgment of the City Manager and Personnel Director it is in the best interests of the City to do so. Promotions shall be on a competitive basis except where the Personnel Director finds that the number of persons qualified for promotion is insufficient to justify competition. Promotional examinations shall give appropriate consideration to the applicant's qualifications, record of performance and seniority. Those found eligible for promotion shall be placed upon a promotional eligible list for the class of positions for which the examination was given, in the rank order of the composite score attained.