7 C.F.R. § 201.59
Tolerances shall be recognized between the percentages or rates of occurrence found by analysis, test, or examination in the administration of the Act and percentages or rates of occurrence required or stated as required by the Act. Tolerances for purity percentages and germination percentages provided for in §§ 201.60 and 201.63 shall be determined from the mean of (a) the results being compared, or (b) the result found by test and the figures shown on a label, or (c) the result found by test and a standard. All other tolerances, including tolerances for pure-live seed and fluorescence, and tolerances for purity based on 10 to 1,000 seeds, seedlings, or plants shall be determined from the result or results found in the administration of the Act.
7 C.F.R. §201.59