(a) Inspection service shall be performed on the basis of the appropriate U.S. standards for grades of processed products, Federal, Military, Veterans Administration or other government agency specifications, written contract specification, or any written specification or instruction which is approved by the Secretary.

(b) Unless otherwise approved by the Director 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 scores of the sample units: Provided further, That:

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

(2) Such sample complies with the product description;

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

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

(i) 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;

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

(iii) The number of sample units classed as deviants does not exceed the applicable acceptance number indicated in the sampling plans contained in § 260.61. A “deviant,” as used in this paragraph, means a sample unit that falls into the next grade below the indicated grade but does not score more than 4 points below the minimum total score for the indicated grade.

(5) 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.