During the assessment proceedings the Assessing Officer has examined the issue of deferred revenue by calling for details and agreed with the accounting system followed by the assessee as regards the accounting of consideration for extended warranty. The AO issued notice u/s 148 for alleged under assessment of income . Objections raised by the Assessee was rejected by the Assessing Officer . The assesee challenged the order of rejection by filing writ petition .  Allowing the petition the Court held that oversight ,inadvertence or mistake of Assessing Officer discovered  on reconsideration of same material. Reassessment is not permissible  Referred Kalyanji Mavji and Co. (1976) 102 ITR 287 (SC). Indian and Eastern Newspaper Society (1979) 119 ITR 996 (SC ) ( Three judges ) ( WPNo. 1145 of 2015 dt 27-1-2021 ( AY. 2009-10)