The director may fix the rates of assessments or fees required by Section 61412 at lesser amounts, and may adjust the rates of assessments or fees from time to time, whenever he or she finds that the cost of administering this article can be defrayed from revenues derived from the lower rates, provided that the rate of assessments deducted from payments to producers for manufacturing milk and the rate of fees paid by manufacturing milk handlers shall at all times be in the ratio of two to one.