As used in this subpart, the term identical means identical within the variation that can be expected to arise as a result of quantity production techniques. (Secs. 4, 303, 307, 48 Stat., as amended, 1066, 1082, 1083; 47 U.S.C. 154, 303, 307) [46 FR 23249, Apr. 24, 1981]