5. Section 15 of the Principal Act is amended—
(a) by omitting from subsection (1) the words “the formula set out in Schedule 2” and substituting “the principles set out in the schedule to the Housing Agreement”; and
(b) by omitting subsection (2) and substituting the following subsection:
“(2) A variation of a housing assistance program prepared under section 12 that alters a rate or amount of rent to be charged shall specify a day, not being a day earlier than the publication of the instrument of variation in the Gazette , from which the alteration is to take effect.”.