“If, on an appeal notified to the tribunal, the tribunal decides- (a) … (b) … (c) that the appellant is overcharged by an assessment other than a self-assessment, The assessment or amounts shall be reduced accordingly, but otherwise the assessment shall stand good.” (a) … (b) … (c) that the appellant is overcharged by an assessment other than a self-assessment, The assessment or amounts shall be reduced accordingly, but otherwise the assessment shall stand good.”