According to 26 USCS § 1388 [Title 26. Internal Revenue Code; Subtitle A. Income Taxes; Chapter 1. Normal Taxes And Surtaxes; Subchapter T. Cooperatives And Their Patrons; Part III. Definitions; Special Rules], the term "per-unit retain allocation" means "any allocation, by an organization to which part I of this subchapter [26 USCS § § 1381 et seq.] applies, to a patron with respect to products marketed for him, the amount of which is fixed without reference to the net earnings of the organization pursuant to an agreement between the organization and the patron."