When any assigned risk plan has become effective as above provided, the superintendent may thereafter disapprove such plan or any portion thereof on the ground that it does not meet the requirements of Section 523 [59A-32-5 N.M. Stat. Ann.] of this article, but only after a full hearing held upon not less than ten (10) days’ written notice to every insurer affected, specifying the matters to be considered at such hearing, and only by an order specifying the respects in which the superintendent finds that such plan fails to meet the requirements imposed, and stating the date, within a reasonable period thereafter, when such plan, or portion thereof, shall be deemed to cease to be effective. No such order shall affect any assignment made or policy issued or made prior to the expiration of the period specified in the order. Amendments to any such plan or plans shall be prepared, filed and reviewed in the same manner as provided with respect to the original plan or plans.