Hon’ble Apex Court in Asstt. CIT v. Rajesh Jhaveri Stock Brokers (P.) Ltd. [2007] 291 ITR 500 in the following terms:-
“It is to be noted that the expressions “intimation” and “assessment order” have been used at different places. The contextual difference between the two expressions has to be understood in the context the expressions are used. Assessment is used as meaning sometimes “the computation of income”, sometimes “the determination of the amount of tax payable” and sometimes “the whole procedure laid down in the Act for imposing liability upon the tax payer”. In the scheme of things, as noted above, the intimation under section 143(1)(a) cannot be treated to be an order of assessment. The distinction is also well brought out by the statutory provisions as they stood at different points of time. Under section 143(1)(a) as it stood prior to April 1, 1989, the Assessing Officer had to pass an assessment order if he decided to accept the return, but under the amended provision, the requirement of passing of an assessment order has been dispensed with and instead an intimation is required to be sent. Various circulars sent by the Central Board of Direct Taxes spell out the intent of the Legislature, i.e., to minimize the departmental work to scrutinize each and every return and to concentrate on selective scrutiny of returns. These aspects were highlighted by one of us (D.K. Jain J) in Apogee International Limited v. Union of India [1996] 220 ITR 248 (Delhi). It may be noted above that under the first proviso to the newly substituted section 143(1), with effect from June 1, 1999, except as provided in the provision itself, the acknowledgment of the return shall be deemed to be an intimation under section 143(1) where (a) either no sum is payable by the assessee, or (b) no refund is due to him. It is significant that the acknowledgment is not done by any Assessing Officer, but mostly by ministerial staff. Can it be said that any “assessment” is done by them? The reply is an emphatic “no”. The intimation under section 143(1)(a) was deemed to be a notice of demand under section 156, for the apparent purpose of making machinery provisions relating to recovery of tax applicable. By such application only recovery indicated to be payable in the intimation became permissible. And nothing more can be inferred from the deeming provision. Therefore, there being no assessment under section 143(1)(a), the question of change of opinion, as contended, does not arise.
2. The aforesaid judgment was was followed by the Division Bench of this Court in CWP No. 17854 of 2007 (Baljit Singh v. CIT decided on 3.12.2007
Summary...... Revised return cannot be filed after regular assessment, but intimation u/s 143(1) is not considered as asessment, as such.
Also refer: https://www.caclubindia.com/experts/revised-return-under-section-139-5--877680.asp