Cap Allowance

1.In calculating cap allowance, could you please brief me as to the order of deducting the limit of 200,000 before moving on to the main and special rate pool. Like are there certain classes of machinery that needs to be first deducted or we only look at the machinery with the highest value? Please
clarify

2.In determing the liability for individual trading income, do we deduct gross gift aid and pension contribution from adjusted net income before considering the appropriate level of personal allowance always? And if the individual is an additional payer, we extend the basic and high rate bamds only.. right?