The Assessing Officer completed a best judgment assessment under section 144 after the assessee failed to comply with notices and estimated the business income at 2 per cent. of the bank credits. The Principal Commissioner revised the assessment under section 263 on the ground that the income ought to have been estimated differently. The Tribunal held that section 144 confers statutory discretion on the Assessing Officer to make a best judgment assessment and such exercise of discretion cannot be revised merely because the Principal Commissioner prefers a different estimate. The order was neither erroneous nor prejudicial to the interests of the Revenue. The revision was therefore quashed. The Tribunal held that once an assessment is validly completed under section 144 after considering the available material, the Assessing Officer exercises an independent statutory discretion. Such discretion cannot be interfered with under section 263 merely because the revisional authority considers another estimate to be more appropriate (AY. 2014-15).