If the return provided for in NRS 375A.150 is not filed within the time specified in that section or the extension specified in NRS 375A.155, then the personal representative shall pay, except as otherwise provided in NRS 360.232 and 360.320, and in addition to the interest provided in NRS 375A.205, a penalty equal to 5 percent of the tax due, as finally determined, for each month or portion of a month during which that failure to file continues, not exceeding 25 percent in the aggregate, unless it is shown that there was reasonable cause for the failure to file. If a similar penalty for failure to file timely the federal estate tax return is waived, that waiver shall be deemed to constitute reasonable cause for purposes of this section.