Refunds for declared provisions require repayment of duties collected that would not have been due under the enacted provision. Refunds are mandated where a declared provision becomes law in amended form within the provisional period or ceases to have effect; duties collected that would not have been collected under the enacted provision must be refunded, subject in the amended-entry case to a cap equal to the difference between the declared provision's proposed rate and the rate in force when the Bill was introduced.