(b) Notwithstanding subdivision (a), any member of the commission, immediately after a vote of the commission in accordance with subdivision (a), may call for a weighted vote. For an item to be passed by weighted vote, all of the following requirements shall be met:

1. (1) The item shall be approved by a majority of the commission members present at the meeting who represent the board of supervisors, who each shall have one vote.
2. (2) The item shall be approved by a majority of the commission members present at the meeting who represent cities in Riverside County, who each shall have one vote.
3. (3) The item shall be approved by commission members present at the meeting who represent cities in Riverside County representing a majority of the population of the county living in incorporated areas. For the purpose of this paragraph, each regular commission member at the meeting who represents a city in Riverside County shall be assigned votes based on the percentage of the population of incorporated areas of Riverside County represented by that member in relation to the total population of incorporated areas of Riverside County represented at the meeting. Population data shall be determined through Department of Finance estimates, adjusted annually.