Tenn. Code § 67-6-534
Notwithstanding § 67-6-806(a), if a nine-digit zip code designation is not available for a street address, or if a seller is unable to determine the nine-digit zip code designation of a purchaser after exercising due diligence to determine the designation, the seller may apply the rate for the five-digit zip code area. For the purposes of this section, there is a rebuttable presumption that a seller has exercised due diligence if the seller has attempted to determine the nine-digit zip code designation by utilizing software approved by the member states to the Streamlined Sales and Use Tax Agreement that makes this designation from the street address and the five-digit zip code of the purchaser. This section does not apply when the product purchased is received by the purchaser at the business location of the seller.
T.C.A. § 67-6-534