Inspection service shall be performed on the basis of the appropriate United States standards for grades of processed products, Federal, Military, Veterans Administration or other government agency specifications, written contract specifications, or any written specification or instruction which is approved by the Administrator.

Unless otherwise approved by the Administrator, compliance with such grade standards, specifications, or instructions shall be determined by evaluating the product, or sample, in accordance with the requirements of such standards, specifications or instructions: Provided, That when inspection for quality is based on any U.S. grade standard which contains a scoring system, the grade to be assigned to a lot is the grade indicated by the average of the total of the scores of the respective sample units: Provided further, That—

Such sample complies with the applicable standards of quality promulgated under the Federal Food, Drug, and Cosmetic Act;

Such sample complies with the product description;

Such sample meets the indicated grade with respect to factors of quality which are not rated by score points; and

With respect to those factors of quality which are rated by score points, each of the following requirements is met:

None of the sample units falls more than one grade below the indicated grade because of any quality factor to which a limiting rule applies;

None of the sample units falls more than 4 score points below the minimum total score for the indicated grade;

The number of deviants does not exceed the applicable acceptance number indicated in the sampling plans contained in § 52.38 (“deviants”, as used in this paragraph, means sample units that fall into the next grade below the indicated grade but do not score more than 4 points below the minimum total score for the indicated grade);

If any of the provisions contained in paragraphs (b) (3) and (4) of this section are not met, the grade is determined by considering such provisions in connection with succeedingly lower grades until the grade of the lot, if assignable, is established; and

When it is determined that a portion of a lot bearing a particular identification mark is of lower quality or deficient in other factors, the grade or compliance of the lot shall be no higher than that of the portion bearing the particular identification mark.