In case of dispute in which a review is desired of the grading of any official sample of cottonseed covered by a valid certificate issued by a licensed cottonseed chemist, application therefor shall be filed with or mailed to a supervisor of cottonseed inspection within ten days after the date of the original certificate, whereupon the licensed chemist issuing the certificate shall immediately surrender to such supervisor the retained portion of the original sample, together with such records as may be required, for the determination of the true grade. The supervisor shall assign to such retained portion an identification number, shall divide such retained portion into two parts and submit the parts to two other licensed cottonseed chemists for reanalysis. Should the supervisor determine that such reanalyses indicate a grade differing from the original by not more than plus or minus one full grade, the original grade shall be considered the true grade. Should he find that such reanalyses indicate a grade differing more than plus or minus one full grade from the original, he shall determine the true grade. In any case, the supervisor shall issue over his name an appeal cottonseed grade certificate showing the true grade as determined in accordance with this section, which shall supersede the licensed chemists' certificates relating to the grade of such seed. Where due solely to errors in calculation or clerical error a grade certificated by a licensed cottonseed chemist is not the true grade, the supervisor shall direct the licensee to cancel the original and to issue a correct certificate. Should such error be found after an application for review has been filed, the supervisor shall nevertheless issue an appeal cottonseed grade certificate showing the true grade of the cottonseed involved.