Refund of duty for Re-export cargo,whether it is drawback under section 74 or refund of duty under section 27 of the Customs Act 1962

This depends on case to case basis for the goods in question.At what stage of Asseement, cleared for Home-consumption or not,whether payment has acquired the characteristics of the duty, whether it is repair or return cargo,whether ,it is temporary import of the machinary,etc,would decide whether it is refund case or drawback case.

The conceptually if the goods are exported goods then it is draw back case and if they are imported goods then it is case of the refund.

what is imported goods?

If goods were not cleared for Home consumption. Then the goods remained Imported goods only .You have to file refund claim for any duty paid on such imported cargo.
But the payment has not acquired the characteristics of the duty and it is deposit in anticipation of duty liability.
The provision of Section 27 are attracted only for Refund of duty and not for Refund of duty deposit. In the present case, the goods were not cleared for Home consumption. No passing of duty incidence can take place, as good never crossed Customs barrier. Even Assessment was not completed.