(a) The department by rule shall allow a license holder to have a single postharvest test performed on a representative sample of plants from a plot if the results of the preharvest test representing the plot show a delta-9 tetrahydrocannabinol concentration of more than 0.3 percent on a dry weight basis.
(b) The department by rule shall prescribe the requirements for a representative sample and for sample collection under this section.

(c) If a license holder fails to request postharvest testing on or before the 15th day after the date the license holder is notified of the results of the preharvest test, the results of the preharvest test are final.