If the Tax Commissioner decides after informal hearing that the tax was not assessed in accordance with the laws, rules and regulations pertaining thereto, he shall make such adjustments as are necessary to correct the assessment and then give written authority to the Treasurer of Guam to make any necessary refund where the tax has been overpaid, or he shall assess the tax as determined, or he shall abate such assessment, as may be necessary.

SOURCE: GC § 19505.