Upon finding a biological need or public need or unsold licenses, including tags and permits, the commission is authorized to order a discount in fees for specific species, units, areas, zones, or gender as necessary to encourage increased license sales or to encourage hunting, fishing or trapping. The commission is also authorized to order a discount in fees to encourage the purchase of licenses in consecutive years or to encourage the purchase of multiple tags and permits. Notwithstanding the provisions of other law to the contrary, any discounted fee shall be effective only for the time period set by the commission order, and holders of licenses purchased before the discount shall not be entitled to a refund except as provided by rule.