Paragraph 159: General deduction rules
3696.This paragraph reflects the fact that in certain sections detailed rules have been provided for the calculation of amounts charged to tax but similar rules have not been spelled out at other places where those rules may apply. Those detailed rules in part reflect the interpretation of the source legislation in case law. This paragraph ensures that the absence of the provision of detailed rules at any point does not prejudice the continued application of existing rules for the meaning of words such as “the full amount of the income”.