(7) In computing the contribution rates, only the wages reported by employers liable for payment of contributions into the fund and net benefits paid that are charged to an employer's experience rating record or to the fund are considered in the computation of the average benefit cost rate and the ratio of total wages to taxable wages.

C. The commissioner shall:

(1) Promptly notify each employer of the employer's rate of contributions as determined for the 12-month period commencing January 1st of each year. The determination is conclusive and binding upon the employer unless within 30 days after notice of the determination is mailed to the employer's last known address or, in the absence of mailing, within 30 days after the delivery of the notice, the employer files an application for review and redetermination, setting forth the employer's reasons. If the commission grants the review, the employer must be promptly notified and must be granted an opportunity for a hearing. An employer does not have standing in any proceedings involving the employer's rate of contributions or contribution liability to contest the chargeability to the employer's experience rating record of any benefits paid in accordance with a determination, redetermination or decision pursuant to section 1194, except upon the ground that the services for which benefits were found to be chargeable did not constitute services performed in employment for the employer and only when the employer was not a party to the determination, redetermination or decision or to any other proceedings under this chapter in which the character of the services was determined. The employer must be promptly notified of the commission's denial of the employer's application or the commission's redetermination, both of which are subject to appeal pursuant to Title 5, chapter 375, subchapter VII; and