The evaluation of competency of a civil employee shall be made pursuant to Section 24 of the Act and the civil employee who secures the highest marks shall be promoted first of all.
Provided that, in respect of the civil employees securing equal marks on the evaluation of competency, promotion shall be made on the basis of seniority; and the determination of seniority of such employees shall be made on the following basis:
(a) On the basis of the date of appointment or decision for promotion in the class of post held at the moment,
(b) On the basis of date of appointment or decision for promotion in the class that is one level lower than such class if seniority cannot be determined pursuant to Clause (a),
(c) On the basis of the merit list recommended by the Public Service Commission if seniority cannot be determined on any basis mentioned in Clauses (a) and (b).
Provided that, in cases where recommendation of the open competition and that of the competition for promotion have been received from the Public Service Commission on the same date, the seniority of an employee recommended through open competition shall be maintained.