(1)  For the purposes of this Part, the average of the actual measurements of a number of like articles is to be determined by calculating the average of the measurements of the contents of at least 12 packages or, if less than 12 are available, of such number (not less than 6) as are available.

(2)  If more than 12 packages are available, the actual number to be tested is to be as determined by an inspector.

(3)  Each of the packages measured must be of the same kind and have the same measurement marking and must be selected by an inspector without having been measured by an inspector.