All records and reports required by this subpart must be maintained separately, chronologically by transaction or reporting date, at the importer's principal place of business. The appropriate TTB officer may, pursuant to a written request, authorize files, or an individual file, to be maintained at another business location under the control of the importer, provided that the alternative location does not cause undue inconvenience to TTB when attempting to examine the files and does not delay the timely transmittal of any documents required to be submitted to TTB.