The following persons shall be authorized, but are not required, to obtain licenses as public weighmasters:
(1) A law enforcement or weights and measures official, or other qualified employee of a state, city, or county agency or institution when acting within the scope of such person's official duties. The commissioner shall be authorized, but is not required, to waive the registration fee for these individuals;
(2) A person weighing property, produce, commodities, or article: That such person or such person's employer is either buying or selling; or
(3) In conformity with the requirements of federal statutes or the statutes of this state relative to warehousemen or processors.