Dear Mr.Partha
The Chapter VI of Finance Act 2015 clearly laids down the following
"The provisions of Chapter V of the Finance Act, 1994 and the rules made thereunder, including those relating to refunds and exemptions from tax, interest and imposition of penalty shall, as far as may be, apply in relation to the levy and collection of the Swachh Bharat Cess on taxable services, as they apply in relation to the levy and collection of tax on such taxable services under Chapter V of the Finance Act, 1994 or the rules made thereunder, as the case may be.”
Since this chapter is notified from November 15th 2015 all the provisions as applicable to service tax are applicable to swach bharath cess.
Hence the interest need to be calculated as it is calculated to service tax
Please refer the fllowing link for more details
https://www.cbec.gov.in/resources//htdocs-cbec/press-release/faq-sbc.pdf
Hope it is clear