(b) by reason of the death of the decedent property passes or is acquired from the decedent under a will executed or a trust created prior to February first, two thousand which contains a formula providing, in sum or substance, for a bequest of the maximum amount of property that can be sheltered from federal estate tax by reason of available credits against such tax; and
(c) such formula was not amended at any time after January thirty-first, two thousand and before the death of the decedent, then, unless the instrument containing such formula specifically provides that there are non-tax reasons for taking the federal credit for state death taxes into account, such formula shall be deemed not to include a reference to the federal credit for state death taxes.