A taxing authority is not entitled to arbitrarily select a figure and impose it on a taxpayer without a rational basis for choosing that figure over another.

“A taxing authority is not entitled to pluck a figure from the air and impose it upon a taxpayer without some rational basis for arriving at that figure and not another figure. Such action would be arbitrary, capricious and in bad faith. It would be an unreasonable exercise of power and discretion and that would justify the Court in intervening."