Sec. 18. (a) This section does not apply to the consent of an agency or local office that is served with notice under IC 31-19-4.5 and has lawful custody of a child whose adoption is being sought.
(b) The consent of a person who is served with notice under IC 31-19-4.5 to adoption is irrevocably implied without further court action if the person:
(1) fails to file a motion to contest the adoption under IC 31-19-10 not later than fifteen (15) days after service of notice under IC 31-19-4.5; or
(2) files a motion to contest the adoption under IC 31-19-10 and the motion is dismissed by the court under IC 31-19-10-1.2(g) or is otherwise denied by the court.