(2) In a policy providing a loss-of-time benefit which may be payable for at least two years, an insurer may at its option insert the following between the first and second sentences of the provision set forth in subsection (1) of this section: "Subject to the qualifications set forth below, if the insured suffers loss of time on account of disability for which indemnity may be payable for at least two years, the insured shall, at least once in every six months after having given notice of claim, give to the insurer notice of continuance of such disability, except in the event of legal incapacity. The period of six months following any filing of proof by the insured or any payment by the insurer on account of such claim or any denial of liability in whole or in part by the insurer shall be excluded in applying this provision. Delay in the giving of such notice shall not impair the insured’s right to any indemnity which would otherwise have accrued during the period of six months preceding the date on which such notice is actually given." [1967 c.359 §433]