1The profits of any pre-war trade year shall be computed on the same principles and subject to the same provisions as the profits of the accounting period are computed.
2Where the accounting period for which the excess profits duty is to be assessed is less than a year, the amount of the pre-war standard of profits shall be proportionately reduced.
3Where it is shown to the satisfaction of the Commissioners of Inland Revenue in the case of any trade or business that the three last pre-war trade years have been years of abnormal depression, any four of the last six pre-war trade years may be substituted for the purposes of the pre-war standard of profits for any two of the three last; pre-war trade years. The three last pre-war trade years shall not be considered as years of abnormal depression unless the average profits of those years have been at least twenty-five per cent. lower than the average profits of the preceding three years.
4Where owing to the recent commencement of a trade or business there have not been three pre-war trade years, but there have been two pre-war trade years, the pre-war standard of profits shall be taken to be the amount of the profits arising from the trade or business on the average of those two years or, at the option of the taxpayer, the profits arising from the trade or business during the last of those two years, and where there have not been two pre-war trade years, but there has been one pre-war trade year, the pre-war standard of profits shall be taken to be the profits arising from the trade or business during that year ; and where there has not been one pre-war trade .year, the pre-war standard of profits shall be taken to be the statutory percentage on the average amount of capital employed in the trade or business during the accounting period. Where the trade or business is an agency or business of a nature involving capital of a comparatively small amount, the pre-war standard of profits shall be computed by reference to the profits arising from any trade, business, office, employment or profession of any sort, whether liable to excess profits duty or not, carried on by the agent or other person before his new trade or business commenced as if it was the same trade or business ; but only to the extent to which the income from the former trade, business, office, employment or profession has been diminished.
5Where since the commencement of the three last pre-war trade years a trade or business has changed ownership, the provisions of this Part of this Schedule shall apply as if a new trade or business had been commenced on the change of ownership, except in cases when the taxpayer makes an application that the provisions of Part III of this Act and this Schedule should apply as if the trade or business had not changed ownership, but in that case such modifications (if any) shall be made in the application of this Schedule as may be necessary to. make the basis on which the profits standard is computed the same as that on which the profits of the accounting period are computed.
6It is hereby declared that, where any business or trade is confined to the management of any particular assets, but power exists to substitute other assets for those particular assets or any of them, such a substitution shall not be deemed, for the purposes of Part III of this Act, to constitute a change of ownership of the business ; but, where any such substitution has been carried out- by the sale of assets and the purchase of other assets, the capital of the trade or business shall be taken to be increased or decreased, as the case may be, only by the amount of the difference between the price of the - assets purchased and the price obtained for the assets sold, and the capital representing the assets purchased shall be estimated on the same basis for all the purposes of Part III of this Act.