434. The decision made by the Minister in accordance with the second paragraph of section 432 shall have effect for the unelapsed period of the then current school year and for the two subsequent school years. Thereafter, the number fixed by the Minister shall remain the same unless all the school boards which are members of the regional board request the Minister to revise the decision made in accordance with the second paragraph of section 432. The decision of the Minister on such request shall come into force upon the expiry of thirty days from the notice of it which he gives in the Gazette officielle du Québec.