1. (a) Taxpayer accounts may be audited by authorized representatives of the comptroller at any time during regular business hours at the discretion of the comptroller or the comptroller's authorized agent or representative.
2. (b) The comptroller may use a detailed auditing procedure or a sample and projection auditing method to determine tax liability. Sampling procedure may include manual sampling techniques and computer-assisted audit techniques, whichever produce the most accurate results in the most efficient manner.

3. (c) A sample and projection auditing method is appropriate if:

   1. (1) the taxpayer's records are so detailed, complex, or voluminous that an audit of all detailed records would be unreasonable or impractical;
   2. (2) the taxpayer's records are inadequate or insufficient, so that a competent audit for the period in question is not otherwise possible; or
   3. (3) the cost of an audit of all detailed records to the taxpayer or to the state will be unreasonable in relation to the benefits derived, and sampling procedures will produce a reasonable result.
4. (d) Before using a sample technique to establish a tax liability, the comptroller must notify the taxpayer in writing of the sampling procedure to be used.
5. (e) If records are inadequate to accurately reflect the business operations of the taxpayer, the auditor will determine the best information available and base the audit report on that information. See §3.281 of this title (relating to Records Required; Information Required) for information on proper records.

6. (f) Resale and exemption certificates.

   1. (1) Resale and exemption certificates should be available at the time of the audit. All certificates obtained on or after the date the comptroller's auditor actually begins work on the audit at the seller's place of business or on the seller's records after the entrance conference are subject to verification. All incomplete certificates will be disallowed regardless of when they were obtained.
   2. (2) The seller has 60 days from the date written notice is received by the seller from the comptroller in which to deliver the certificates to the comptroller. Written notice shall be given by the comptroller upon the filing of a petition for redetermination or claim for refund. For the purposes of this section, written notice given by mail is presumed to have been received by the seller within three business days from the date of deposit in the custody of the United States Postal Service. The seller may overcome the presumption by submitting proof from the United States Postal Service or by other competent evidence showing a later delivery date. If the seller is not in possession of the certificates within 60 days from the date written notice is given by the comptroller that certificates pertaining to periods or transactions specified in the notice are required, any deductions claimed which require resale or exemption certificates will be disallowed. Exemptions claimed by those certificates acquired during this 60-day period will be subject to independent verification by the comptroller before the deductions will be allowed. Certificates delivered after the 60-day period will not be accepted. See §3.285 of this title (relating to Sales for Resale; Resale Certificate); §3.287 of this title (relating to Exemption Certificates); and §3.288 of this title (relating to Direct Payment Procedures and Qualifications).
   3. (3) When a 60-day letter has been received, a resale or exemption certificate is the only acceptable proof that a taxable item was purchased for resale or qualifies for exemption.
7. (g) Both sellers and purchasers are subject to audit and assessment of tax on any transactions on which tax was due but has not been paid.
8. (h) The comptroller may proceed against either the seller or purchaser, or against both, until the tax, penalty, and interest have been paid.

Source Note:The provisions of this §3.282 adopted to be effective January 1, 1976; amended to be effective December 21, 1983, 8 TexReg 5037; amended to be effective December 31, 1984, 9 TexReg 6333; amended to be effective August 5, 1985, 10 TexReg 2321; amended to be effective September 16, 1991, 16 TexReg 4844.