Whether the Additional / Joint Commissioner can withdraw the summary assessment order only on application by the taxable person

The Additional / Joint Commissioner can, on his own motion may withdraw the summary assessment order in the event such order is erroneous and thereafter may follow the procedure laid down in Section 73 or 74 which provides for determination of tax liability on account of tax not paid other than fraud, wilful mis-statement etc., or otherwise . The order of withdrawal or, rejection of the application under Section 64(2) shall be issued in FORM GST ASMT-18.

(ICAI FAQ PUBLICATIONS 0609-2017 SUMMARY ASSESSMENT IN CERTAIN SPECIAL CASES: FAQ NO. 27)

What is the remedy available to the taxable person if the order passed u/s 64 is erroneous

On an application made in FORM GST ASMT–17 within 30 days by taxable person from the date of receipt of order passed summary assessment order the Additional/Joint Commissioner may withdraw such order and follow the procedure laid down in Section 73 or 74 which provides for determination of tax liability on account of tax not paid other than fraud, wilful mis-statement etc., or otherwise.

(ICAI FAQ PUBLICATIONS 06-09-2017 SUMMARY ASSESSMENT IN CERTAIN SPECIAL CASES: FAQ NO. 26)

What is the Time limit for passing the assessment order on the unregistered person

The proper officer, in relation to assessment of taxes on the unregistered taxable person, shall issue the assessment order in FORM GST ASMT-15 within 5 years from the date specified under Section 44 for furnishing of the annual return for the financial year to which the tax not paid relates.

(ICAI FAQ PUBLICATIONS 06-09-2017 ASSESSMENT OF UNREGISTERED PERSONS: FAQ NO. 21)

Whether, The CGST Act, 2017 provides for assessment of taxes on the unregistered taxable person who fails to take registration even though liable to do so? What will be the procedure of such assessment

If a taxable person fails to obtain registration even though liable to do so or whose registration has been cancelled under section 29(2) but who was liable to pay tax, the proper officer may assess the tax liability to the best of his judgement after providing opportunity of being heard to such person.
The proper officer shall issue a notice to a taxable person in FORM GST ASMT-14 containing the grounds on which the assessment is proposed to be made on best judgment basis.                                                                                                                     The registered person will be allowed a time of fifteen days to furnish his reply.

(ICAI FAQ PUBLICATIONS 06-09-2017 ASSESSMENT OF UNREGISTERED PERSONS : FAQ NO.  20)