The annual term of service and compensation of members of the several county boards of equalization shall be on a basis of total assessed value of all taxable property, using the year 1955 as the basis, to be determined as follows:

(1) In those counties in which the total assessed value of all taxable property exceeds $600,000,000 according to the tax assessor's abstract of assessments for said year, except in a county subject to subdivision (2) of this section, the members of the county boards of equalization shall serve on a full-time basis, and each associate member shall be paid at the rate of $19,425 per annum, and the chairman shall be paid at the rate of $21,090 per annum, payable in monthly installments.

(2) This subdivision shall apply to any county of this state which has a population of 600,000 or more according to the last or any subsequent federal census and in which the total assessed value of all taxable property exceeds $600,000,000 according to the tax assessor's abstract of assessments for said year.

In any county subject to this subdivision, the members of the county board of equalization shall serve on a full-time basis. Each associate member shall be paid at the rate of $19,425 per annum, and the chairman's total compensation shall be determined as provided for by the merit system law applying to the county, and the chairman shall be subject to and entitled to the benefits of the law establishing such merit system. The chairman's total compensation shall be payable from the general funds of the county, and the chairman shall promptly pay to the county any compensation he or she receives from the State of Alabama and from the largest municipality of the county for serving as chairman. In addition to the salary provided for the chairman under the merit system law, the county shall make for and on the chairman's account an employer's matching payment to the county pension system fund, if the chairman is or becomes a member of the county pension system.

(3) In those counties in which the total assessed value of all taxable property exceeds $400,000,000 and does not exceed $600,000,000 according to the tax assessor's abstract of assessments for said year, the members of the county board of equalization shall serve on a full-time basis, and each associate member shall be paid at the rate of $8,700 per annum, and the chairman shall be paid at the rate of $9,200 per annum, payable in monthly installments.

(4) In those counties in which the total assessed value of all taxable property is not less than $80,000,000 and does not exceed $400,000,000 according to the tax assessor's abstract of assessments for said year, the members of the county board of equalization shall serve for not less than six months, the exact working period to be fixed or approved by the Department of Revenue, and each member shall be paid at the rate of $250 per month; and said board shall be allowed annual traveling expenses to be approved by the Department of Revenue not to exceed the sum of $250 for any tax year.

(5) In those counties in which the total assessed value of all taxable property is not less than $30,000,000 and does not exceed $80,000,000 according to the tax assessor's abstract of assessments for said year, the members of the county board of equalization shall serve for not more than 150 working days, the exact working period to be fixed or approved by the Department of Revenue, and each member shall be paid at the rate of $35 per diem; and said board shall be allowed mileage at the same rate as that paid to state employees, for official business, payable in the same manner and from the same source as expense allowances; provided however, the total allowance for such mileage shall not exceed the sum of $600 per annum.

(6) In those counties in which the total assessed value of all taxable property is not less than $25,000,000 and does not exceed $30,000,000, according to the tax assessor's abstract of assessments for said year, the members of the county board of equalization shall serve for not more than 80 working days, the exact working period to be fixed or approved by the Department of Revenue, and shall be paid at the rate of $35 each per diem, payable in monthly installments; and said board shall be allowed mileage at the same rate as that paid to state employees, for official business, payable in the same manner and from the same source as expense allowances; provided however, the total allowance for such mileage shall not exceed the sum of $600 per annum.

(7) In those counties in which the total assessed value of all taxable property does not exceed $25,000,000 according to the tax assessor's abstract of assessments for said year, the members of the county board of equalization shall serve for not more than 80 working days, the exact working period to be fixed or approved by the Department of Revenue, and each member shall be paid at the rate of $35 per diem, payable in monthly installments; and said board shall be allowed mileage at the same rate as that paid to state employees, for official business, payable in the same manner and from the same source as expense allowances; provided however, the total allowance for such mileage shall not exceed the sum of $600 per annum.