Special computation for small retail and service businesses: simplified deemed income scheme requiring statement submission and advance tax payment. Special computation permits qualifying small retailers, small eating place operators, small transport operators and specified vocations to treat a prescribed deemed amount as their business or vocation profits when they submit a prescribed, verified statement and pay advance tax on the deemed income and minimal other taxable income; applicability is subject to turnover and income ceilings, absence of prior assessments for certain earlier years, definitions of covered activities and timely submission with proof of payment.