If a condominium property for which the declaration was filed with a county recorder prior to October 1, 1978, has been expanded by the addition of units in accordance with the declaration, and if the unit owners do not commence an action to contest the change in the undivided interests in the common elements in a court of competent jurisdiction within two years after the date that the amendment was filed with the county recorder, each of the unit owners of the condominium property as expanded is deemed to have assented to and ratified the amendment, and the undivided interests in the common elements of the unit owners is no longer contestable.