Pursuant to N.C. Gen. Stat. § 50-13.4(f)(1), the court may require the responsible parent to execute an assignment of wages, salary, or other income due or to become due whenever his employer’s voluntary written acceptance of the wage assignment under N.C. Gen. Stat. § 95-31 is filed with the court. Such acceptance remains effective until the employer files an express written revocation with the court. The amount assigned shall be increased by an additional one dollar ($1.00) processing fee to be assessed and retained by the employer for each payment under the order. (1981, c. 275, s. 7; 1983 (Reg. Sess., 1984), c. 1047, s. 2.)