3-2. Roche, in its report for the half-year ended June 30, 20X0 with the following disclosure: 'Impairment of assets'. When the recoverable amount of an asset, being the higher of its net selling price and its value in use, is less than its carrying amount, then the carrying amount is reduced to its recoverable value. This reduction is reported as an impairment loss. Value in use is calculated using estimated cash flows, generally over a five-year period, with extrapolating projections for subsequent years. These are discounted using an appropriate long-term interest rate. Previously the permitted alternative method for calculating value in use was applied, whereby it was calculated using cash flow projections on an undiscounted basis. As a result, the Group recognized impairment charges of 1,161 million Swiss francs relating to acquired intangible assets. As a result of the impairment, the net book value of intangible assets was reduced by the amount of the impairment charge, and consequently amortization in the first half of 20X0 was 64 million Swiss francs lower than it would have been under the previous policy. Required: a) What are the accounting effects of this change? b) What are the possible reasons behind this change in determining the value in use? c) Summarize the main challenges in performing an impairment test for intangible assets?