Sec. 6. (a) The department of state revenue may accept a probate court's determination of the inheritance tax due as a result of a decedent's death as a provisional estimate of the inheritance tax imposed.
(b) If the final determination of federal estate tax shows a change in the fair market value of the assets of a decedent's estate or a change in deductions, the department of state revenue may petition or cause other persons to petition the probate court which has jurisdiction for a redetermination of the inheritance tax imposed as a result of the decedent's death. The petition must be filed within sixty (60) days after a copy of the final determination of federal estate tax is filed with the department as required by IC 6-4.1-4-8. An inheritance tax redetermination which is made under this section is limited to modifications based on either a change in the fair market value of the assets of the decedent's estate or a change in deductions.