(a) If it shall be impossible to compute the present value of any of the property transferred, or of any interest in such property, or if the tax cannot be determined because of a contingency as to who will take it, the commissioner of revenue, with the written approval of the attorney general and reporter, may enter into an agreement with the representatives of the estate or the transferees, or both, to compound the tax upon such terms as may be deemed equitable, and the payment of any amount agreed upon shall be in full satisfaction for the tax imposed by this part and part 4 of this chapter, and such amount shall be payable out of the property transferred.
(b) If such an agreement cannot be reached, the taxation of the property or interest shall be held in abeyance and the commissioner shall require the representatives of the estate or transferees, or both, to give bond for the prompt payment of the tax at such time as the value of the property or interest, of the transferees, may be determined, and such tax shall bear interest as provided in subsection (a). The amount of the bond shall be fixed and the sufficiency of the surety determined by the commissioner.