Dear Sir,
Now in GST there no more exist concept of double Invoices i.e Commercial Invoice and GST Invoices.
Reason : If we register commerical Invoice with Customs and Give in GSTR return the Tax Invoice then there will be invoice mismatch.
The normal process what generally is followed is to mention USD in GST Invoice with Equivalent INR (2 Columns).
It will help to solve 2 purposes simultaneouly ie.
1. Bill Regularization Issues : A Bank will want GST Invoice and Not Commercial Invoice to Regularize the SEZ Bill (BRC In case we want to discharge our EPCG Obligation/Advance Authorization Obligation)
2. Only 1 Accounting Invoice : It would be simple to mention in narration or in reference only Details of Tax Invoices instead of mentioning the Details of Commerical invoice again in narration.
Regards