The scale of charges shall be established as follows:
(a)
If all the produce dealers in a market, or a majority of such produce dealers, either individually or through group representation, have an agreement with a union, the scale of charges shall be that which is prescribed in such agreement and approved as provided in this chapter. If an agreement which covers any employees of produce dealers in a market does not cover persons who unload farm products, the agreement shall be modified, or a new agreement made, to cover such persons.
(b)
If there is no such union, the scale of charges shall be fixed by the produce dealers that operate within the market.
In either event, the scale of charges is subject to the approval of the director.