(decedent's estate satisfied requirements of I.R.C. Sec. 6166 and made election to pay estate tax in installments; estate failed to pay interest for 2010 and 2011 on deferred amounts of estate tax and IRS issued final notice and demand for payment; court determined that requirements of I.R.C. Sec. 6166(g)(3)(A) satisfied and election to pay estate tax via I.R.C. Sec. 6166 terminated as matter of law; unpaid portion of estate tax due on notice and demand). Annotation