(6) A provision for certificates issued on and after January first, nineteen hundred seventy-five, that after three full years' premiums have been paid or, in the case of certificates that provide that the certificate holder may vary the amount and frequency of premiums to be paid to the society, after three years from the issue of the certificate, if the certificate is in force and not in default, the society will, at any time while the certificate is in force, advance, on proper assignment or pledge of the certificate and on the sole security thereof, a sum equal to, or at the option of the person entitled thereto, less than, the amount of the cash surrender value calculated in accordance with the provisions of section four thousand five hundred eleven of this article; and that the society may deduct from such loan value (in addition to the indebtedness deducted in determining such value) any unpaid balance of the premium for the current certificate year; and that if the loan is made or repaid on a date other than the anniversary of the certificate the society may collect interest for the portion of the current certificate year on a pro rata basis. The certificate shall provide, at the option of the society, either that (i) any such loan shall bear interest at a maximum rate of not more than seven and four-tenths per centum per annum if payable in advance or the equivalent effective rate of interest if otherwise payable, or (ii) any such loan shall bear interest at a rate not in excess of an adjustable maximum rate established from time to time by the society as permitted by law. If the certificate provides for an adjustable rate, the certificate shall specify the regular intervals at which the interest rate is to be determined which shall be at least once every twelve months, but not more frequently than once in any three month period. The certificate may further provide that if the interest on the loan is not paid when due, it shall be added to the existing loan, and shall bear interest at the applicable rate or rates payable on the loan determined in accordance with the provisions of the certificate; and subject to subsection (e) of section three thousand two hundred six of this chapter may further provide that if and when the total indebtedness on the certificate, including interest due or accrued, equals or exceeds the amount of the loan value thereof at such time, and if at least thirty days' prior notice shall have been given in the manner provided in section three thousand two hundred eleven of this chapter, then the certificate shall terminate and become void. This provision shall not apply to term insurance. Any certificate which provides for the crediting of additional amounts pursuant to section four thousand five hundred eighteen of this article may also provide that if any indebtedness is owed to the society on any part of the loan value which would otherwise be credited with additional amounts, such additional amounts may be reduced so that the total amounts credited on such part are so credited at a rate that is up to two percent per annum less than the applicable loan interest rate charged or at such other rate as the superintendent, upon the society's demonstrating justification therefor, may allow.