The commission, not later than October 1 of each year, shall establish the assessment for the marketing season that begins September 1 and continues through August 31 of the following year, which shall not exceed 5 percent of the average price received by producers, computed on a per pound basis or computed in any other manner determined by the commission to be reasonably equivalent to the per pound computation. The commission may revise the assessment established prior to October 1 of each year if it determines, based on information including crop volume, that the action is necessary, and if the revision does not exceed the assessment limitations specified in this section and the modification is made prior to the date established by the commission for payment of the assessment.