(a) Unless otherwise provided by regulation, all notices and petitions to the commission shall be given in writing and delivered by first class mail or by hand, addressed to the Waterfront Commission of New York Harbor, at its main administrative offices. If delivered by mail, notice shall be deemed given only when actually received.

(b) All notices and communications from the commission, other than those specified in section 6.3 of this Title, shall be duly served if enclosed in a properly post-paid wrapper addressed to the person to be notified or communicated with at the address last given by him in writing to the commission and deposited, as ordinary mail, in a post office, post office box, or mail chute maintained by the United States government, or if such notice or communication addressed to such person is delivered to such address by telegram or by registered or certified mail or by an employee or agent of the commission. Such service shall be deemed as having been made in the regular course of the business of the commission, without any certification of such service by an employee or agent of the commission. For the purpose of calculating the time of notice, service shall be considered effected upon the date of delivery to such address; provided that, where service is by ordinary mail, service shall be considered effective the third day after the mailing.