A classification plan for the employees in the classified service of the City of Toledo and Board of Health shall be adopted and maintained by the Commission. The plan shall provide for the standardization and classification of all positions in the classified service. All of the positions in the classified service shall be so grouped and arranged that each class shall consist of those positions so similar in respect to the duties, responsibilities and authority that the same descriptive title may be used to designate each position allocated to the class, that the same requirements as to education, experience, capacity, knowledge, proficiency, ability and other qualifications should be required of the incumbents, that the same tests of fitness may be used to choose qualified eligibles and that the same schedule of compensation may be made to apply with equity.