(

a) Notwithstanding any other provision of law, including, but not limited to,

Chapter 10 (commencing with

Section 3500) of Division of Title 1, no resolution, ordinance, contract, or contract amendment under this

chapter adopted on or after January 1, 2004, may provide any retirement benefits for some, but not all, general members of a county or district. (

b) No resolution, ordinance, contract, or contract amendment under this

chapter adopted on or after January 1, 2004, may provide different retirement benefits for any subgroup of general members within a membership classification, including, but not limited to, bargaining units or unrepresented groups, unless benefits provided by statute for members hired on or after the date specified in the resolution are adopted by the county or district governing board, by resolution adopted by majority vote, pursuant to a memorandum of understanding made under the Meyers-Milias-Brown Act (Chapter 10 (commencing with

Section 3500) of Division of Title 2). All nonrepresented employees within similar job classifications as employees in a bargaining unit subject to a memorandum of understanding, or supervisors and managers thereof, shall be subject to the same formula for the calculation of retirement benefits applicable to the employees in the bargaining unit. No retirement contract amendment may be imposed by the employer in absence of a memorandum of understanding under the Meyers-Milias-Brown Act. (

c) This

section does not preclude changing membership classification from one membership classification to another membership classification. (

d) This

section shall not apply to retirement benefits for a member described in paragraph (2) of subdivision (

d) of

Section 31676.15.