If the Clerk-Treasurer is not satisfied with the return and payment of taxes made by any person under the provisions of this chapter, he or she is hereby authorized and empowered to make an additional assessment of the tax due by the taxpayer, based upon the facts contained in the return or otherwise acquired. Promptly after the date of the additional assessment, the Clerk-Treasurer shall give or send by mail a notice thereof to the person, together with written notice of a time when, and the place where, the person may be heard on a petition for reassessment as hereinafter provided.