Retroactive preservation of pre-amendment treatment for notices on duty shortfalls and erroneous refunds remains in force. The substituted Explanation 4 retrospectively (from 29 March 2018) declares that notices issued before that date for non-levy, short-levy, non-payment, short-payment or erroneous refund shall continue to be governed by the version of section 28 that existed immediately before 29 March 2018, notwithstanding any inconsistent court or tribunal orders, other provisions of the Act, rules, regulations or other law.