In order to assist the Executive to give effect to the housing benefit scheme under Part VII of the Social Security Contributions and Benefits (Northern Ireland) Act 1992 (c. 7), where a rent is registered in the register of rents, there shall be entered in the register the amount (if any) of the registered rent which, in the opinion of the rent officer or rent assessment committee, is fairly attributable to the provision of services, except any amount which is negligible in the opinion of the rent officer or, as the case may be, the rent assessment committee.