“In Rahman ( No 2 ) the tribunal had made their own assessment of the correct amount of VAT due from the taxpayer. They had reduced the Commissioners' 73(1) assessment by about 50%. The submission that I was addressing in paragraph 32 of my judgment in that appeal was to the effect that, where there has been a substantial reduction by the tribunal in the assessments made by the Commissioners on the same material, it must inevitably follow that the Commissioners' assessment was not made to the best of their judgment. In rejecting that submission I said this: '[32] ... But non sequitur: on a true analysis all that can be said is that the fact that, on considering the same material, the tribunal has reached a figure for the VAT payable which differs from that assessed by the commissioners requires some explanation. The explanation may be that the tribunal, applying its own judgment to the same underlying material at the second, or "quantum", stage of the appeal, has made different assumptions--say, as to food/drink ratios, wastage or pilferage--from those made by the commissioners. ... Or the explanation may be that the tribunal is satisfied that the commissioners have made a mistake--that they have misunderstood or misinterpreted the material which was before them, adopted a wrong methodology or, more simply, made a miscalculation in computing the amount of VAT payable from their own figures. In such cases--of which the present is one--the relevant question is whether the mistake is consistent with an honest and genuine attempt to make a reasoned assessment of the VAT payable; or is of such a nature that it compels the conclusion that no officer seeking to exercise best judgment could have made it. Or there may be no explanation; in which case the proper inference may be that the assessment was, indeed arbitrary”