Each basic no-fault insurer of the owner of a secured motor vehicle shall also make available optional excess no-fault benefits for excess economic loss commencing upon the exhaustion of basic no-fault benefits, up to a total of eighty thousand dollars in no-fault benefits for accidental bodily injury to any one person in any one accident, including an accident when the person who purchased the optional excess no-fault benefits or that person’s relative is injured in a motor vehicle not owned by the insured or as a pedestrian. A basic no-fault insurer may also offer benefits and limits other than those prescribed in this section, and a basic no-fault insurer may incorporate in optional excess no-fault coverage the terms, conditions, and exclusions as may be consistent with the premiums charged. The amounts payable under optional excess no-fault benefits may be duplicative of benefits received from any collateral sources or may be written in excess of such collateral source benefits, or may provide for reasonable waiting period, deductibles, or coinsurance provisions. The optional excess no-fault benefits of a basic no-fault insurer may provide for subrogation to the injured person’s right of recovery against any responsible third party.