Written plan.) Each common trust fund shall be established, administered and maintained in accordance with a written declaration of trust, herein referred to as the “plan”, prepared by the bank or trust company and approved by resolution of its board of directors. The plan shall make provision, not inconsistent with this Act, as to the following matters: (1) the manner in which the fund is to be operated, (2) the investment powers of the bank or trust company with respect to the fund, including the character and kind of investments which may be purchased for the fund, (3) the allocation and apportionment of income, profits and losses, (4) the terms and conditions governing the admission or withdrawal of investments or participations in the fund, (5) the auditing and settlement of accounts of the bank or trust company with respect to the fund, (6) the basis and method of valuing assets in the fund, (7) the basis upon which the fund may be terminated, and (8) such other matters as may be necessary or proper to define clearly the rights of participants in the common trust fund. The plan may provide that if a bond or other obligation for the payment of money is acquired as an investment for any common trust fund at a cost in excess of the par or maturity value thereof, such excess cost need not be amortized out of income within the common trust fund itself; if the plan, however, should provide for the amortization of such excess cost out of the income of such obligation, then such amortization shall be made during but not beyond the period that such obligation is held as an investment in such fund by deducting from each receipt of income and adding to principal an amount equal to the sum obtained by dividing such excess cost by the number of periodic payments of income to accrue on such obligation from the date of such acquisition until its maturity date. The plan may provide that Series G United States Savings Bonds, or any other United States Bonds of any kind or series which are purchasable at a price equivalent to the maturity value thereof and which provide for a decline in redemption value at any time or times between purchase and maturity, (a) may be purchased at any time for the common trust fund, (b) may be transferred from a participating trust to the common trust fund at par or maturity value in lieu of a contribution of money, and (c) shall at all times and for all purposes of the common trust fund be valued at par or maturity value. The provisions of the plan shall control all participations in the fund and the rights and benefits of all persons interested in such participations, as beneficiaries or otherwise. The plan may be amended from time to time pursuant to resolution of the board of directors of the bank or trust company. A copy of the plan shall be available at the principal office of the bank or trust company and any affiliate thereof during all regular business hours, for inspection by any person having an interest in a trust, any funds of which are invested in a participation in the common trust fund, and upon reasonable request a copy of the plan shall be furnished to such person.