(a) The interest cost to the authority computed on the basis of the interest rates borne by the bonds refunded and by the refunding bonds, will be increased by reason of the refunding; or
(b) The average maturity of the bonds refunded, computed to their stated maturities will be increased by reason of the refunding; or
(c) The time at which bonds may be redeemed is more than twelve (12) months after the date of sale of the refunding bonds;
(d) However, if it can be clearly shown that the refunding is being accomplished to prevent default or to provide flexibility to the authority in the financing of its projects, and if the State Treasurer shall certify that the need to refund an outstanding issue to prevent default or to provide flexibility to the authority in the financing of its projects has been determined by sufficient evidence filed with the State Treasurer, the provisions of subsections (a), (b) and (c) shall not prevent refunding.