(

a) Notwithstanding any other provision of this part, a school employer, the employees’ exclusive representative, and unrepresented employees may agree that the employer contribution for postretirement health coverage shall be subject to the following:

(1) Credited years of service that the employee worked with the contracting agency.

(2) A memorandum of understanding regarding postretirement health coverage mutually agreed upon through collective bargaining. This issue may not be subject to the impasse procedures set forth in

Article 9 (commencing with

Section 3548) of

Chapter 10.7 of Division of Title 1. (

b) No agreement reached pursuant to subdivision (

a) shall be valid if it imposes separate postretirement health coverage vesting requirements on employees in the same category and doing similar job duties. (

c) This

section is not applicable to any employee who retired before the effective date of the memorandum of understanding. In the event that the memorandum of understanding establishes a retroactive effective date, this

section applies only prospectively and any employee who retires before the memorandum of understanding is signed may not be affected by it. (

d) No agreement reached pursuant to subdivision (

a) shall be valid if it provides an employer contribution for employees with less than five years of credited service with the school employer. (

e) The contracting agency shall provide, in the manner prescribed by the board, a notification of the agreement established pursuant to this

section and any additional information necessary to implement this section.