(2)Subject to the other provisions of this section, the authority concerned-(a)may make an amendment under sub-section (1) of its own motion, and(b)shall make such amendment for rectifying any such mistake which has been brought to its notice by the assessee, and where the authority concerned is the [* * *] [ Certain words omitted by Act 21 of 1998, Section 65 (w.e.f. 1.10.1998).] [Commissioner (Appeals)] [ Inserted by Act 29 of 1977, Section 29 (w.e.f. 10.7.1978).], by the [Assessing Officer] [ Substituted by Act 4 of 1988, Section 2, for " Income-tax Officer" (w.e.f. 1.4.1988).] also.[* * *] [ Proviso omitted by Act 32 of 1994, Section 38 (w.e.f. 1.6.1994).]