In the event that the periods stipulated in items (i) to (iv) of paragraph (3) of Article 12 of the Act are three months or more preceding the day on which there arises a need for calculation of a worker's average wage, or in the event there arises a need for calculation of a worker's average wage on the day that the worker is taken into employment, the average wage of the worker shall be stipulated by the directors of the prefectural labor offices.