(a) If it deems it to be in the public interest, the legislative body may amend all or part of an adopted general plan. An amendment to the general plan shall be initiated in the manner specified by the legislative body. Notwithstanding Section 66016, a legislative body that permits persons to request an amendment of the general plan may require that an amount equal to the estimated cost of preparing the amendment be deposited with the planning agency prior to the preparation of the amendment.
(b) Except as otherwise provided in subdivision (c) or (d), no mandatory element of a general plan shall be amended more frequently than four times during any calendar year. Subject to that limitation, an amendment may be made at any time, as determined by the legislative body. Each amendment may include more than one change to the general plan.
(c) The limitation on the frequency of amendments to a general plan contained in subdivision (b) does not apply to amendments of the general plan requested and necessary for a single development of residential units, at least 25 percent of which will be occupied by or available to persons and families of low or moderate income, as defined by Section 50093 of the Health and Safety Code. The specified percentage of low- or moderate-income housing may be developed on the same site as the other residential units proposed for development, or on another site or sites encompassed by the general plan, in which case the combined total number of residential units shall be considered a single development proposal for purposes of this section.
(d) This section does not apply to the adoption of any element of a general plan or to the amendment of any element of a general plan in order to comply with any of the following:
(1) A court decision made pursuant to Article 14 (commencing with Section 65750).
(2) Subdivision (b) of Section 65302.3.
(3) Subdivision (b) of Section 30500 of the Public Resources Code.