expenditure was incurred previously by the company or another company in acquiring, leasing, bringing into existence or enhancing the value of the asset, and

any of that expenditure has been taken into account, or would on the applicable assumption have been taken into account, for the purposes of the levy.

any case where the asset acquired is an interest in an oil field, and

any case where the asset is acquired in connection with a transfer to the company of an interest in an oil field (whether or not the asset is acquired at the time of the transfer).

any reference to expenditure incurred by a company in leasing an asset is to expenditure incurred by it under an agreement under which the asset was leased to the company,

any reference to the applicable assumption in the case of any expenditure incurred at any time is to the assumption that this Act were fully in force and applied to expenditure incurred at that time, and

any reference to an interest in an oil field is to the whole or part of the equity in an oil field.