No changes. Interest rate ( As per otification no. No. 6/2011) is 18% p.a on service tax if value of taxable service is more than Rs. 60 Lakhs and if less than Rs. 60 Lakh, you have to pay 15% p.a. interest on service tax if you do not pay service tax within the due date. The new rate of interest of 18% p.a. is applicable from 1st April, 2011.