No assessment shall be made or issued against a vendor or transient guest for any tax imposed by or pursuant to this chapter more than four years after the return date for the period in which the lodging was furnished, or more than four years after the return for such period is filed, whichever is later. The division does not bar an assessment:
(a) When the Auditor has substantial evidence of amounts of taxes collected by a vendor from transient guests' lodging which were not returned by the City.
(b) When the vendor assessed failed to file a return as required.
(Ord. 73-89. Passed 9-18-89.)