Office audit.

The department shall, as soon as practicable, office audit such returns as it deems advisable and if it is found from such office audit that a person has been over or under assessed, or found that no assessment has been made when one should have been made, the department shall correct or assess the income of such person. Any assessment, correction or adjustment made as a result of such office audit shall be presumed to be the result of an audit of the return only, and such office audit shall not be deemed a verification of any item in said return unless the amount of such item and the propriety thereof shall have been determined after hearing and review as provided in s. 71.88 (1) (a) and (2) (a). Such office audit shall not preclude the department from making field audits of the books and records of the taxpayer and from making further adjustment, correction and assessment of income.