(1)    Filing procedure. Except as provided in sub. (2), every authorized insurer and every rate service organization licensed under s. 625.31 which has been designated by any insurer for the filing of rates under s. 625.15 (2) shall file with the commissioner all rates and supplementary rate information and all changes and amendments thereof made by it for use in this state within 30 days after they become effective.

   (2)   Consent to rate. Upon written application of the insured, stating the insured’s reasons therefor, filed with and not disapproved by the commissioner within 10 days after filing, a rate in excess of that provided by a filing otherwise applicable may be applied to any specific risk. The rate may be disapproved without a hearing, subject to s. 601.62 (3). If disapproved, the rate otherwise applicable applies from the effective date of the policy, but the insurer may cancel the policy proportionally on 10 days’ notice to the policyholder. If the insurer does not cancel the policy the insurer shall refund any excess premium from the effective date of the policy.