This section does not apply to an amended estate tax return. Subject to § 13-601 of this article, the Comptroller may extend the time to file an estate tax return up to 6 months, or if the person required to file the estate tax return is out of the United States, up to 1 year. An estate that is afforded a later due date for filing the federal estate tax return under the Internal Revenue Code shall be afforded the same later due date for filing the Maryland estate tax return. A request for an extension of time to file the Maryland estate tax return shall be filed on a form prescribed by the Comptroller.