(a) The commissioner shall, when a county is in its digest review year, approve the digest of any such county as being reasonably uniform and equalized if the digest meets the following criteria:

(1) The average assessment ratio for each class of property within the county shall be as close to the assessments provided for in Code Section 48-5-7 as is reasonably practicable;

(2) The average assessment variance for each class of property within the county shall not be excessive with respect to that which is reasonably practicable; and

(3) Within each class of property, assessment ratios of the properties shall not reveal any significant assessment bias.

(b) The commissioner shall by regulation establish the statistical standards to be used in determining whether or not digests are in accordance with the uniformity requirements contained in subsection (a) of this Code section. The commissioner shall utilize information developed by the state auditor under Code Section 48-5-274.

(c) If the assessed value of the portion of the digest that does not meet the uniformity requirements constitutes 10 percent or less of the assessed value of the total digest, the commissioner may approve the digest if, in his judgment, the approval will not substantially violate the concept of uniformity and equalization.