Upon the filing of an application under either Section 38-73-1300 or 38-73-1310 the director or his designee shall set a time and place for a hearing at which the insurer and the rating organization may be heard and shall give them not less than thirty days' written notice thereof. In the event the director or his designee is advised by the rating organization that it does not desire a hearing he may, upon the consent of the applicant, waive the hearing. In considering an application under Section 38-73-1300 for permission to file a deviation the director or his designee shall give consideration to the available statistics and the principles for rate making as provided in Section 38-73-330. The director or his designee shall issue an order permitting the deviation or modification for the insurer to be filed if he finds it to be justified. Upon issuance of the order the deviation or modification becomes effective. The director or his designee shall issue an order denying the application if he finds that the resulting premiums would be excessive, inadequate, or unfairly discriminatory or, in the case of an application filed under Section 38-73-1310, if he finds the modification requested is not justified. Each deviation permitted to be filed, which, when approved, would result in a uniform percentage decrease, remains effective until disapproved by the director or his designee. Each deviation permitted to be filed, which, when approved, would result in a uniform percentage increase, is effective for a period of one year from the date of the permission unless terminated sooner with the approval of the director or his designee.