(1) This section is subject to the vesting requirements of section 42b.

  (2) Unless the qualified participant affirmatively elects not to contribute or elects to contribute a lesser amount, the qualified participant shall contribute 2% of his or her compensation to his or her Tier 2 account. The qualified participant’s employer shall make a contribution to the qualified participant’s Tier 2 account in an amount equal to 50% of the first 2% of compensation contribution made by the qualified participant under this subsection.

  (3) A qualified participant may make contributions in addition to contributions made under subsection (2) to his or her Tier 2 account as permitted by the department and the internal revenue code.