When a lot of apples is required to meet one of the U.S. grades, the apples shall not be further advanced in maturity than generally firm ripe, and the following tolerances, by weight, shall apply:
(a) For defects. 10 percent for apples which fail to meet the requirements of the grade: Provided, That included in this amount not more than the following percentages shall be allowed for the defects listed:
(1) 2 percent for apples which are affected by decay;
(2) 2 percent for apples which are affected by internal breakdown; and,
(3) 5 percent for apples which are affected by worm holes.
(b) For off-size. 5 percent for apples which are smaller than any specified minimum size, and 10 percent for apples larger than any specified maximum size.