Dear CA Sowmya Mam,
My views are as under under:
A. CGST Audit officer is indeed officer of Central Tax.
B. Notified 'proper officers' include such CGST Audit officers as per Notification No.2/2017-Central Tax.
C. Para 6 of Circular No. 31/05/2018 - GST is NOT issued using powers using clause (91) of section 2 of the CGST Act read with section 20 of the IGST Act.
D. It is worth noting that Circular No. 3/3/2017 - GST as well as Para 2 & Para 5 (but NOT Para 6) of Circular No. 31/05/2018 - GST are issued using powers using clause (91) of section 2 of the CGST Act read with section 20 of the IGST Act and are subject to sub-section (2) of section 5 of the CGST Act.
E. Most importantly, one needs to take note of Notification No.2/2017-Central Tax, where 'proper officers' which is notified using the powers under section 3 read with section 5 of the CGST Act and section 3 of the IGST Act. Please note Para 1 of said notification where there is no distinction between officers working in "Principal Commissionerate" and "Audit Commissionerate" and vests them with ALL the powers under both the said Acts and the rules made thereunder with respect to the jurisdiction specified in the Tables given below in said notification.
E1. Here, distinction between cases made by DGCI & audit-wing also needs to be noted in view of the followings:
E2. Specific Table V (i.e. Powers of Additional Commissioner or Joint Commissioner of Central Tax for passing an order or decisionin respect of notices issued by the officers of Directorate General of Goods and Services Tax Intelligence) needs to be noted with Para 3A of said notification which reads as follows:
Notwithstanding anything contained in paragraph 3, the Additional Commissioners or the Joint Commissioners of Central Tax, as the case may be, subordinate to the Principal Commissioners of Central Tax or the Commissioners of Central Tax, as specified in column (2) of Table V, are hereby vested with the powers as specified in the corresponding entry in Column (3) of the said Table.
E3. However, no such distinction (i.e .special arrangement) is made for audit-wing of CGST. This has be seen from Table - IV under said notification (i.e. Jurisdiction of Commissioner of Central Tax (Audit)) read with Para 5 of said notification which reads as follows:
The Commissioners of Central Tax (Audit) specified in column (2) of Table IV and the central tax officers subordinate to them are hereby vested with the territorial jurisdiction of the Principal Commissioners of Central Tax or the Commissioners of Central Tax, as the case may be, specified in the corresponding entry in column (3) of the said Table.
F. In view of above, Para 6 of Circular No. 31/05/2018 - GST - as far as its audit-wing is concerned - is more in nature of guidelines / desire / internal instruction of the Board and same has NOT conferred "any legal right" to the person facing SCN and its adjudication.
F1. Hence, said Para 6 cannot be used by a tax-payer to claim "undeniable legal right" to challenge the validity of issuance of SCN as well as adjudication of such SCN by Dept's audit-wing officer.
G. Summarising above, in my humble view, such audit-wing officer is indeed notified as "proper office" to issue SCN and adjudicate the same as per Notification No.2/2017-Central Tax.
H. Lastly, as far as I know, there is no legal bar - currently present - which prevents CGST officer, who has conducted audit, to issue SCN (against audit objections) and adjudicate such SCN.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion. And I respect contrary views.