(a) Any union representing registered unloaders is authorized and entitled to bargain with the employer of the registered unloaders to establish a scale of charges for unloading produce.
(b) If the union or unions representing registered unloaders and the employer of registered unloaders are unable to agree on a scale of charges, the Public Employment Relations Board shall mediate the dispute pursuant to Section 3601 of the Government Code.
(c) The scale of charges in effect on December 31, 1978, shall remain in effect until new charges are established pursuant to this section.