Sale of royalty oil under this article is for processing or use in the purchaser’s refineries but not for resale in kind. Agreements providing for the exchange of refinery charge stocks on a volume or equivalent value basis are not a resale in kind prohibited by this section. If an exchange agreement has been entered into or is contemplated with regard to royalty oil available for sale, full information relating to such fact shall be furnished to the department either at the time of filing applications to purchase royalty oil or with the submission of a bid.