(1) Said refunding bonds shall be issued in such denominations as the board shall determine, but in the same denominations so far as practicable as the bonds to be refunded and shall mature at the date specified in the notice of election but not in any event later than thirty years from the date thereof, and shall be payable in minimum annual installments specified on a percentage basis and amortized to provide for full payment of the bonds with interest at maturity: PROVIDED, That in lieu of the annual payments of principal and semiannual payments of interest as provided in this chapter, the court may prescribe the form, manner of payment, and interest rate or rates of the refunding bonds, in the decree determining maximum benefits and irrigable acreage; and said decree may grant the district the right to pay at the date of any annual or semiannual payment, one or more next accruing annual or semiannual installments less the interest on that part of the principal thus paid in advance: AND PROVIDED, In all cases in which the court determines the form, manner of payment, and interest rate of the refunding bonds in the decree determining maximum benefits, all notices provided in this chapter and any other provision thereof, shall be given and construed in conformity with the terms and conditions of said bond prescribed in said decree. Such bonds may be in any registered form as provided for in RCW
39.46.030.