Income-tax filing in India is no longer a form-filling task. Pre-filled data, the Annual Information Statement (AIS), a default new tax regime and an expanding set of return forms mean that two taxpayers with similar gross income can face very different filing paths. This paper reports a practice-based study carried out during a twelve-week on-the-job training placement (11 May – 3 August 2026) at a Pune-based tax-advisory firm that combines professional review with workflow automation. It asks (1) how taxpayer profile shapes the filing pathway, (2) when the old tax regime outperforms the new regime for individuals in Assessment Year 2026–27, and (3) which control points in a hybrid advisory workflow reduce avoidable error. The paper contributes a fourteen-stage filing workflow with explicit control points, a rule-based ITR applicability matrix, a transparent regime-comparison model with computed break-even deductions, and a case-complexity score. Using the model, a salaried taxpayer with ₹18 lakh gross salary needs about ₹6.42 lakh of old-regime deductions beyond the standard deduction to match the new regime, a level that few salaried taxpayers reach. Case-mix and process-performance figures in the paper are illustrative and are labelled as such; they demonstrate a measurement design and are not verified firm records. The study argues that professional advisory creates most value in classification, reconciliation and decision documentation rather than in computation alone.

Keywords: income-tax filing; taxpayer segmentation; old versus new tax regime; ITR selection; AIS reconciliation; tax advisory; digital tax administration; India