A. Taxes levied under this Part shall only be subject to interest as provided for in R.S. 47:1601, and such interest shall begin to accrue nine months after the date of death of the decedent and shall continue to accrue until the tax is paid. Notwithstanding any other provision of law to the contrary, no penalty or interest shall apply or be assessed when the succession is opened no later than the last day of the ninth month following the death of the decedent.
B. The secretary may accept an extension of time to file a United States Estate Tax Return for the same decedent as an extension of time to file a Louisiana estate transfer tax return.