With respect to applications filed on and after the effective date of this section by a unified district and any apportionments and repayments made under the applications, “grade level maintained by the district” means the kindergarten, if any, and grades 1 to 12, inclusive, maintained by the district.

A unified district if otherwise eligible, may apply for and receive an apportionment for either one or both of the grade levels.

This section shall not apply to a unified district

during the first three years following the effective date of this section, or during the first three fiscal years in which the district is in existence for all purposes, if the governing board of the district transmits to the board a written notice stating the district desires to be exempted from this section during that period.