This may be desirable for some taxable persons where: • it is not possible or not practical to identify different ADT exemptions and liabilities from the taxable person’s transaction- based systems; • the complexity of the taxable person’s business is such that an individual passenger transaction-by-transaction approach would be impractical because of the time required to identify the correct amounts of ADT; or • the nature of the business is such that passenger numbers are not normally recorded.