The following regulations apply: If it is apparent that a mechanical or clerical error was made in the calculation of the assessment, the assessment is adjusted. On the date of finality, if the assessment office was unaware of the existence of a condition affecting value, the assessment may be adjusted. If the basis for a request for reduction is a difference of opinion or a difference in valuation judgment, relief is denied. Tax-Property Article, §§2-201, 2-202, and 8-419, Annotated Code of Maryland Effective date: January 7, 1982 (8:26 Md. R. 2106)