Gst % on supplementary invoices

Karthik (Student CA Final ) (50 Points)

30 May 2018  

For a customer, we need to raise Supplementary invoices (Period is June 2017 to September 2017)

In November 15, the GST rates have been changed for the materail from 28% to 18%

How much GST % need to be done on Supplementary invoices ???

Pls help me in this....