A long-form educational deep-dive on Other Income as a percentage of Profit Before Tax — the 30-second forensic earnings-quality filter that separates real Indian operating businesses from non-operating bookkeepers. Illustrated using Titan Biotech FY25 audited disclosures (operating-led ~₹214 Cr revenue, ~18-22% EBITDA margin, CFO/Operating Profit at ~103%, total borrowings ₹3 Cr) as a positive educational example. Educational content only — not a buy/sell recommendation.