Retrospective amendment preserves pre-amendment governance for customs levy and refund notices issued before commencement of the finance Act. The amendment substitutes Explanation 4 to declare that, notwithstanding any conflicting judgments, provisions, rules or other laws, notices issued before commencement of the Finance Act, 2018 for non-levy, short-levy, non-payment, short-payment or erroneous refund shall continue to be governed by the version of section 28 in force immediately before that commencement; the substitution is retrospective to that commencement date.