GSt On carriage service in the course of export

IGST ........you have yourself answered to your query .
Even though supplier & Recepient are in same state IGST will be applicable.

In this regard, we can hope clarification from the Board otherwise there will be problem regarding determination of place of supply which may further create confusion in availing ITC whether on CGST/SGST or IGST. Sooner the clarification, less the problems for assessees.

But right Now it's clear that IGST is applicable