The civil service director shall, as soon as practicable after sections 383C.03 to 383C.059 take effect and after consultation with appointing authorities and principal supervising officials, recommend to the county civil service commission a classification plan, together with proposed rules for its administration. Such classification plan shall show each class of positions in the classified service, and when approved by the county civil service commission, shall be made public, together with the rules for its administration. Each such class shall include such positions requiring duties which are substantially similar in respect to duties and responsibilities and shall be designated by titles indicative of the duties; and that the same schedule of compensation can be made to apply with equity under like working conditions. The class titles shall be used in personnel, budget and financial records and communications. As far as practicable the natural or probable line of promotion to and from the class of positions shall be designated or indicated.