Rectification u/s 154

The assessee is a public company and in the ITR6 for AY 17-18, there was a mistake in capital gains computation where COA was erroneously written as 1.40 crores instead of 1.14 crores. Due to b/f business losses, tax liability for the year was NIL and the error did not draw assessee's attention.

Subsequently, 143(3) order was passed where some additions were made on a different matter by AO. During assessment proceedings, Capital Gains was never a topic for consideration.

After indexation, the impact of the clerical error is huge.

Does this seem like a case where a rectification petition u/s 154(1) might lead to relief for assessee?
This is a mistake apparent from record but I am unsure if petition can be filed in the above circumstance.
What other avenues are available for relief in such a case?

Any help will be highly appreciated.