(2) Save as otherwise provided in this section, all other provisions of this Act shall apply accordingly as if the modified return is a return furnished under section 139.

(3) If the assessment or reassessment proceedings for an assessment year relevant to a previous year to which the agreement applies have been completed before the expiry of period allowed for furnishing of modified return under sub-section (1), the Assessing Officer shall, in a case where modified return is filed in accordance with the provisions of sub-section (1), ⁵⁴[pass an order modifying the total income of the relevant assessment year determined in such assessment or reassessment, as the case may be,] having regard to and in accordance with the agreement.

(4) Where the assessment or reassessment proceedings for an assessment year relevant to the previous year to which the agreement applies are pending on the date of filing of modified return in accordance with the provisions of sub-section (1), the Assessing Officer shall proceed to complete the assessment or reassessment proceedings in accordance with the agreement taking into consideration the modified return so furnished.

(5) Notwithstanding anything contained in section 153 or section 153B or section 144C,—

 (a) the order ⁵⁵[***] under sub-section (3) shall be passed within a period of one year from the end of the financial year in which the modified return under sub-section (1) is furnished;

 (b) the period of limitation as provided in section 153 or section 153B or section 144C for completion of pending assessment or reassessment proceedings referred to in sub-section (4) shall be extended by a period of twelve months.

(6) For the purposes of this section,—

  (i) "agreement" means an agreement referred to in sub-section (1) of section 92CC;

 (ii) the assessment or reassessment proceedings for an assessment year shall be deemed to have been completed where—

  (a) an assessment or reassessment order has been passed; or

  (b) no notice has been issued under sub-section (2) of section 143 till the expiry of the limitation period provided under the said section.