Section 760 ILCS 15/3 - Scope of Act; rules of administration(a) This Act governs the ascertainment of income and principal and the apportionment of receipts and expenses in all cases where a trust is established unless otherwise stated hereinafter, to the extent not inconsistent with the provisions of the instrument. A person establishing a trust may make provision in the instrument for the manner of ascertainment of income and principal and the apportionment of receipts and expenses or grant discretion to the trustee to do so and such provision, where not otherwise contrary to law, shall control notwithstanding this Act.(b) A trust shall be administered with due regard to the respective interests of income beneficiaries and remaindermen. A trust is so administered with respect to the allocation of receipts and expenses if a receipt is credited or an expense is charged to income or principal or partly to each: (1) in accordance with the terms of the instrument, notwithstanding contrary provisions of this Act; or(2) in the absence of any contrary terms of the instrument, in accordance with the provisions of this Act or, if the trustee in the trustee's discretion determines that application of the provisions of this Act would result in a substantial inequity to either the income beneficiaries or the remaindermen, in accordance with what is reasonable and equitable in view of the interests of those entitled to income as well as those entitled to principal; or(3) if neither of the preceding rules of administration is applicable, in accordance with what is reasonable and equitable in view of the interests of those entitled to income as well as of those entitled to principal.(c) If the instrument or paragraph (2) of subsection (b) gives the trustee discretion in crediting a receipt or charging an expense to income or principal or partly to each, no inference of imprudence or partiality arises from the fact that the trustee makes an allocation other than in accordance with a provision of this Act or determines not to do so.(d) To the extent not otherwise provided in the instrument or this Act, receipts shall be credited when actually received by the trustee and expenses shall be charged when actually made by the trustee, except that the trustee may elect to credit receipts and charge expenses in any other reasonable manner that complies with the provisions of subsection (b) and is not inconsistent with the terms of the instrument.