Section 961 - Effect of federal determination(a) General.- A final federal determination as to (1) the inclusion in the federal gross estate of any item of property or interest in property,(2) the allowance of any item claimed as a deduction from the federal gross estate, or(3) the value or amount of any such item, shall also determine the same issue for purposes of the tax under this article unless such final federal determination is shown by a preponderance of the evidence to be erroneous.(b) Definition.- For the purpose of this section a final federal determination means: (1) A decision by the tax court or a judgment, decree or other order by any court of competent jurisdiction which has become final.(2) A final disposition by the secretary of the treasury or his delegate of a claim for refund. Such disposition shall be deemed to have occurred- (A) as to items of the claim which are allowed, upon allowance of refund or upon disallowance of the claim by reason of offsetting items; and(B) as to items of the claim which are disallowed, or as to items applied by the secretary of the treasury or his delegate as an offset against the claim, (i) upon expiration of the time for instituting suit for refund with respect to such items, unless suit is instituted before the expiration of such time, or (ii) upon filing with the surrogate or appraiser a written statement, in such form as may be required by the tax commission, that suit for refund will not be instituted. (3) A closing agreement made under section seven thousand one hundred twenty-one of the internal revenue code.(4) An assessment pursuant to a waiver of restrictions on assessment, or a notification in writing issued by the secretary of the treasury or his delegate that the federal estate tax return has been accepted as filed where such notification is issued after an audit of such return, unless the executor shall have filed with the commissioner of taxation and finance a written statement, in such form as may be required by the commissioner, that a claim for refund of federal estate taxes has been or will be filed.(c) Items determined.- If there has been a final federal determination with respect to a decedent's federal estate tax, any item entering into the computation of such tax shall be deemed to have been the subject of the final federal determination, whether or not specifically adjusted thereby.