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