Presumptive taxation under Section 44ADA requires full advance tax payment by the due date; interest applies if default. A person opting for the presumptive taxation scheme under section 44ADA must pay the whole advance tax amount on or before 15 March of the previous year; failure attracts interest under sections 234B and 234C. Any amount paid on or before 31 March is treated as advance tax for the financial year ending that day.