“Section 29(1)(a)”

The expression "for the purpose of business" is wider in scope than "for the purpose of earning profits" and encompasses expenditures made for commercial expediency, business preservation, administration, and modernization.

An assessee should not be prejudiced by differences in accounting treatment if accounting principles are duly followed and the issue is revenue neutral, as hypothetical income cannot be subjected to tax.

Customer acquisition costs and advertisement expenditures are treated as revenue expenditures, not deferred expenditures, as there is no general concept of deferred expenditure for such items under Income Tax Law.

Income tax authorities cannot deduce the nature of a document from purported intention, go behind the document, consider the substance over form, or rewrite it merely to suit the revenue's purpose.

When relevant documents or additional evidence have a direct bearing on an issue, they may be allowed to be produced or admitted at the appellate stage, potentially leading to a de novo adjudication by the Assessing Officer for fresh consideration.

An appellate authority has the jurisdiction to admit additional evidence if it is necessary for a complete and effective adjudication of the matter.

The 'written down value' (WDV) under Section 43(6)(b) is determined by depreciation that has been 'actually allowed', meaning it has been taken into account or granted and given effect to by the Income-tax Officer in computing taxable income.

Section 43B of the Income Tax Act, 1961, which requires certain statutory liabilities to be paid by a specific due date for allowability of deduction, does not apply to service tax if the service tax has not become payable due to non-receipt of payments from the service recipient. This is because section 43B refers to a "sum payable by the assessee".