income of employees by reason of section 106(a) of such Code. (3) Allocation rules For purposes of this section, qualified health plan expenses shall be allocated to qualified family leave wages in such manner as the Secretary of the Treasury (or the Secretary’s delegate) may prescribe. Except as otherwise provided by the Secretary, such allocation shall be treated as properly made if made on the basis of being pro rata among covered employees and pro rata on the basis of periods of coverage (relative to the time periods of leave to which such wages relate). (e) Special rules (1) Denial of double benefit For purposes of chapter 1 of such Code, the gross income of the employer, for the taxable year which includes the last day of any calendar quarter with respect to which a credit is allowed under this section, shall be increased by the amount of such credit. Any wages taken into account in determining the credit allowed under this section shall not be taken into account for purposes of determining the credit allowed under section 45S of such Code . (2) Election not to have section apply This section shall not apply with respect to any employer for any calendar quarter if such employer elects (at such time and in such manner as the Secretary of the Treasury (or the Secretary’s delegate) may prescribe) not to have this section apply. (3) Certain terms Any term used in this section which is also used in chapter 21 of such Code shall have the same meaning as when used in such chapter. (4) Certain governmental employers This credit shall not apply to the Government of the United States, the government of any State or political subdivision thereof, or any agency or instrumentality of any of the foregoing. (f) Regulations The Secretary of the Treasury (or the Secretary’s delegate) shall prescribe such regulations or other guidance as may be necessary to carry out the purposes of this section, including— (1) regulations or other guidance to prevent the avoidance of the purposes of the limitations under this section, (2)