“Tier 2 member”: A person who first becomes a participant under this Article on or after January 1, 2011 and before the implementation date, as defined under subsection (a) of Section 1-161, determined by the Board, other than a person in the self-managed plan established under Section 15-158.2 or a person who makes the election under subsection (c) of Section 1-161, unless the person is otherwise a Tier 1 member. The changes made to this Section by this amendatory Act of the 98th General Assembly are a correction of existing law and are intended to be retroactive to the effective date of Public Act 96-889, notwithstanding the provisions of Section 1-103.1 of this Code.