S.C. Code Ann. § 12-60-440 – Deficiency assessment restrictions

(A) The department may not assess a deficiency until ninety days after sending the proposed assessment as provided in Section 12-60-420, or, if the taxpayer files a timely written protest with the department, until the taxpayer's appeal is finally decided. For purposes of this section, the final decision of an appeal includes the decision of the Administrative Law Judge Division or court, if the matter was heard by the Administrative Law Judge Division or appealed to a court as provided in this article. This restriction on assessments does not apply to:
1. (1) mathematical or clerical errors;
2. (2) interest imposed by this title or subject to assessment or collection by the department;
3. (3) penalties for failure to file or failure to pay, or penalties that are determined as a percentage of interest;
4. (4) amounts reported on a return or other document, or paid as tax; or
5. (5) assessments as provided in Section 12-60-910.
(B) If a proposed assessment was not issued, the taxpayer may request an abatement of an assessment due to a mathematical or clerical error, or for a penalty described in item (3), within thirty days of the date of the assessment. Upon receipt of the request for abatement the department shall abate the assessment. A further assessment of the tax with respect to which an abatement is made under this paragraph is subject to the proposed assessment procedures described in this chapter. A levy or collection proceeding may not begin for a mathematical or clerical error during the thirty-day period during which a taxpayer may request an abatement.