Exemption.

(1) In computing a taxpayer’s liability for tax under this code, there shall be exempt from the tax $50,000 of net income as defined in s. 220.12 or such lesser amount as will, without increasing the taxpayer’s federal income tax liability, provide the state with an amount under this code which is equal to the maximum federal income tax credit which may be available from time to time under federal law.

(2) In the case of a taxable year for a period of less than 12 months, the exemption allowed by this section shall be prorated on the basis of the number of days in such year to 365.

(3) Only one exemption shall be allowed to taxpayers filing a consolidated return under this code.

(4) Notwithstanding any other provision of this code, not more than one exemption under this section may be allowed to the Florida members of a controlled group of corporations, as defined in s. 1563 of the Internal Revenue Code with respect to taxable years ending on or after December 31, 1970, filing separate returns under this code. The exemption described in this section shall be divided equally among such Florida members of the group, unless all of such members consent, at such time and in such manner as the department shall by regulation prescribe, to an apportionment plan providing for an unequal allocation of such exemption.