(1) All taxes imposed by this chapter, unless otherwise provided in this chapter, shall be due at the death of the decedent and shall be payable to the Department of Revenue within eighteen (18) months thereafter. If they are paid within nine (9) months, a discount of five percent (5%) shall be allowed, and if they are paid within eighteen (18) months, no interest shall be charged and collected thereon. If the taxes due are not paid within eighteen (18) months, interest at the tax interest rate as defined in KRS 131.010(6) shall be paid from the expiration of the eighteen (18) months until payment is actually made to the department.
(2) In all cases where the personal representatives or trustees do not pay the taxes within eighteen (18) months from the death of the decedent, they shall be required to give bond, in the form and to the effect prescribed by the department, for the payment of the taxes and interest.