Notwithstanding any provision of this code to the contrary, the term “deductions”, as defined in § 21-5-1 of this code and applied to the wages of an employee of an urban mass transportation authority under this article which is a direct or indirect recipient of federal funding from the Federal Transit Administration pursuant to the Urban Mass Transportation Act of 1964, as amended, includes amounts authorized for union or labor organization dues or fees. This section applies only to urban mass transportation authorities under this article.