A. The said assistant district attorney shall receive as compensation for his services as such officer, in addition to the annual salary paid by the state, an additional salary of eight thousand dollars per annum, payable monthly on his own warrant. The additional salary shall be paid by the parishes comprising the Twenty-Second Judicial District, apportioned as follows:
(1) By the parish of St. Tammany, the sum of four thousand dollars per annum.
(2) By the parish of Washington, the sum of four thousand dollars per annum.
B. Provided, in lieu of the payment by the respective parishes as set forth in Subsection A of this Section, the said additional salary may be paid from the criminal court funds of the respective parishes where the money is available from such funds, all according to law.