Amendment to amortisation under section 35D shortens the write off period, accelerating tax deductions for qualifying capital expenditure. Amendment revises the amortisation schedule under section 35D for expenditure incurred after 31 March 1998, replacing a ten year spread with a five year spread so that one fifth of qualifying expenditure is deductible in each of five successive previous years; a related percentage based measure for aggregate post cutoff expenditure is likewise substituted with a higher rate. These changes take effect from 1 April 1999.