Section 10. The commission shall have the following additional powers, functions and duties:—(a) If the commission determines that the construction or alteration for which an application for a certificate of appropriateness has been filed will be appropriate for or compatible with the preservation or protection of the historic district, the commission shall cause a certificate of appropriateness to be issued to the applicant. In the case of a disapproval of an application for a certificate of appropriateness the commission shall place upon its records the reasons for such determination and shall forthwith cause a notice of its determination, accompanied by a copy of the reasons therefor as set forth in the records of the commission, to be issued to the applicant, and the commission may make recommendations to the applicant with respect to appropriateness of design, arrangement, texture, material and similar features. Prior to the issuance of any disapproval the commission may notify the applicant of its proposed action accompanied by recommendations of changes in the applicant's proposal which, if made, would make the application acceptable to the commission. If within fourteen days of the receipt of such a notice the applicant files a written modification of his application in conformity with the recommended changes of the commission, the commission shall cause a certificate of appropriateness to be issued to the applicant.

(b) In the case of a determination by the commission that an application for a certificate of appropriateness or for a certificate of nonapplicability does not involve any exterior architectural feature, or involves an exterior architectural feature which is not then subject to review by the commission in accordance with the provisions of section eight, the commission shall cause a certificate of nonapplicability to be issued to the applicant.

(c) If the construction or alteration for which an application for a certificate of appropriateness has been filed shall be determined to be inappropriate, or in the event of an application for a certificate of hardship, the commission shall determine whether, owing to conditions especially affecting the building or structure involved, but not affecting the historic district generally, failure to approve an application will involve a substantial hardship, financial or otherwise, to the applicant and whether such application may be approved without substantial detriment to the public welfare and without substantial derogation from the intent and purposes of this chapter. If the commission determines that owing to such conditions failure to approve an application will involve substantial hardship to the applicant and approval thereof may be made without such substantial detriment or derogation, or in the event of failure to make a determination on an application within the time specified in section eleven, the commission shall cause a certificate of hardship to be issued to the applicant.

(d) Each certificate issued by the commission shall be dated and signed by its chairman, vice-chairman, secretary or such other person designated by the commission to sign such certificates on its behalf.

(e) The commission shall keep a permanent record of its resolutions, transactions, and determinations and of the vote of each member participating therein, and may adopt and amend such rules and regulations not inconsistent with the provisions of this act and prescribe such forms as it shall deem desirable and necessary for the regulation of its affairs and the conduct of its business. The commission shall file a copy of any such rules and regulations with the city or town clerk.

(f) The commission shall file with the city or town clerk and with any department of the city or town having authority to issue building permits a copy or notice of all certificates and determinations of disapproval issued by it.

(g) A commission may after public hearing set forth in such manner as it may determine the various designs of certain appurtenances, such as light fixtures, which will meet the requirements of an historic district and a roster of certain colors of paint and roofing materials which will meet the requirements of an historic district, but no such determination shall limit the right of an applicant to present other designs or colors to the commission for its approval.

(h) The commission may, subject to appropriation, employ clerical and technical assistants or consultants and incur other expenses appropriate to the carrying on of its work, and may accept money gifts and expend the same for such purposes. The commission may administer on behalf of the city or town any properties or easements, restrictions or other interests in real property which the city or town may have or may accept as gifts or otherwise and which the city or town may designate the commission as the administrator thereof.

(i) The commission shall have, in addition to the powers, authority and duties granted to it by this act, such other powers, authority and duties as may be delegated or assigned to it from time to time by vote of the city council or town meeting.