The payments of such installments, and such interest charge and the payments thereof, shall be as follows:

(1) If such order is made on or after the first day of January and before the first day of November of any year, the first installment shall be payable on the thirty-first day of December following the date of such order, with interest on the principal, at the rate of six percent per annum, from the date of such order until the first day of April after the date such installment becomes payable, and one installment shall become payable on the thirty-first day of each December thereafter with interest at such rate on the portion of the principal then unpaid, from the thirty-first day of the previous December until the first day of the following April, until the entire assessment is paid.

(2) If such order is made on or after the first day of November of any year, the first installment of such special assessment shall be payable on the thirty-first day of December of the next year after the date of such order, with interest at such rate on the principal from the date of such order until the first day of April after the date such first installment becomes payable, and thereafter an installment shall be payable on the thirty-first day of each December, with interest at such rate on the principal then unpaid, from the thirty-first day of the previous December to the first day of the following April, until the entire principal of the assessment is paid.