Such annual commissions shall be computed either on the value of the principal of the trust or of the property subject to the power in trust at the end of the period for which the commissions are payable or, at the option of the trustee or donee of the power in trust, on the value of the principal of the trust or of the property subject to the power in trust at the beginning of such period, provided that the option elected by the trustee or donee of the power in trust for the first period for which such commissions are payable shall be used during the continuance of the trust or of the power in trust and shall be binding on any successor or substitute trustee or trustees, donee or donees. In the case of a trust which prior to January 1, 1994 computed annual commissions on the basis of a 12 month period (other than a calendar year), the trustee's prior election of such 12 month period shall be binding unless, prior to January 1, 1995, the trustee makes a new election to compute annual commissions on the basis of a calendar year either on the value of the principal of the trust at the end of, or at the option of the trustee at the beginning of, the calendar year for which the commissions were payable, which new election shall be used during the remaining continuance of the trust and shall be binding on any successor or substitute trustee or trustees. The computation shall be made on the basis of a 12-month period but the amount so computed payable to a trustee shall be proportionately reduced or increased for any payments made in partial distribution of the trust or the receipt of any additional property into the trust within such period and shall be proportionately reduced in any period for which such commissions are payable to the trustee if the period is less than 12 months. For the purpose of computing the annual commissions the value of any principal asset when received by the trust or donee of a power in trust shall be the presumptive value of the asset at the beginning and end of the period for which such commissions are payable. In computing the value of the principal of the trust or of the property subject to the power in trust the trustee or donee of the power in trust may use the presumptive value in respect of any principal asset or may use the actual value of the asset. On the settlement of the account of the trustee or donee of a power in trust any person interested may dispute the amount of any commission claimed or retained. The burden of proving that the actual value of any principal asset or asset subject to the power in trust differs from its presumptive value is upon the trustee or donee of a power in trust or other person claiming the difference.
N.Y. Surr. Ct. Proc. Act Law § 2309