(1) Unless expressly prohibited from transferring units of a security by means of any computer-based system, a trustee or personal representative shall not be chargeable with a breach of trust or, as the case may be, with default in administering the estate by reason only of the fact that -

(a) for the purpose of acquiring units of a security which he has the power to acquire in connection with the trust or estate, he has paid for the units under arrangements which provide for them to be transferred to him from a system-member but not to be so transferred until after the payment of the price;

(b) for the purpose of disposing of units of a security which he has power to dispose of in connection with the trust or estate, he has transferred the units to a system-member under arrangements which provide that the price is not to be paid to him until after the transfer is made; or

(c) for the purpose of holding units of a security belonging to the trust or estate in uncertificated form and for transferring title to them by means of a relevant system, he has become a system-member.