For the purpose of the enforcement of this Part, non-intentional technical errors shall mean inaccuracies in the unit pricing information reflected upon a stamp, tag, label, sign or list where such defects have resulted from a malfunction of a printing press, electronic data processing equipment or other mechanical equipment used to produce such stamps, tags, labels, signs, or lists, or from the mistake of a computer programmer or machine operator, where such malfunction or mistake was not within the knowledge or control of the owner or operator or management personnel of the store and where such owner or operator or management personnel could not with reasonable diligence have detected and corrected such errors.