(a) Whenever a deficiency in payment of the assessment is determined, the commission shall give notice thereof to the employer. Such determination shall finally and conclusively fix the amount due, unless the employer shall, within 30 days after the giving of notice of such determination, petition in writing to the commission for a hearing, or unless the commission on its own motion shall reduce the same. A petition for such hearing shall be verified and contain the following information:

1. (1) the name and address of the employer, license number, if any, the period covered by the deficiency and the date of the deficiency notice; and
2. (2) the grounds upon which the petition is based and each error of fact alleged to have been made by the commission in its determination, together with the facts and arguments in support thereof.