Refund of input tax credit formula revised for zero-rated supplies; UIN recognition and registration forms updated. The amendment deems the Unique Identity Number granted under the Central Act to be valid under the Gujarat Act, limits retrospective amendment of registration particulars absent Commissioner's order, revises the refund formula and definitions for input tax credit on zero-rated supplies without payment under bond or letter of undertaking, prescribes separate refund routes where suppliers have availed specified Government Notifications, restricts refund eligibility where recipients received supplies benefiting from those notifications, requires quarterly electronic refund applications through prescribed forms, and substitutes multiple registration and refund forms including for non-resident providers of online services.