Supply of goods and/ or services to or by a SEZ developer or an SEZ unit, shall be deemed to be a supply of goods and/or services in the course of inter-State trade or commerce and would be Zero rated supplies.
However, probably as it exists today such upfront exemptions could be subjected to certain conditions only after fulfilling these conditions it is likely that the SEZs would enjoy the abinitio exemption else, they would have to opt for refund route