712. Determination of appeal.

If, on an appeal notified to the tribunal, the tribunal decides that:

  1.  

    (1)     the appellant is overcharged by a self-assessment;

  2.  

    (2)     any amounts contained in a partnership statement are excessive;

  3.  

    (3)     the appellant is overcharged by an assessment other than a self-assessment,

the assessment or amounts must be reduced accordingly, but otherwise the assessment or statement stands good5.

If, on an appeal notified to the tribunal, the tribunal decides that:

  1.  

    (a)     the appellant is undercharged to tax by a self-assessment;

  2.  

    (b)     any amounts contained in a partnership statement are insufficient; or

  3.  

    (c)     the appellant is undercharged by an assessment other than