Interest rates under SGST fixed for specified default, refund and recovery provisions, including the proviso, varying by provision. Fixes annual interest rates for specified provisions of the West Bengal Goods and Services Tax Ordinance, 2017: differentiated rates for the primary and enhanced interest provisions under section 50, specified rates for refund-related provisions under section 54 and for recovery under section 56, and a distinct rate for the proviso to section 56; the notification is issued under the Ordinance and takes effect from the commencement date stated in the instrument.