Less amount of output tax paid in GSTR-3B as compared to GSTR-1 in 2017-18. Traetment in GSTR-9C

For 2017-18, there is no difference in Taxable value in GSTR-3B, GSTR-1 and books of accounts. However, in GSTR-3B, amount of output tax is paid less as compared to actual tax liability in CGST and SGST due to some difference in rates of tax. It was correctly shown in GSTR-1. 

This additional tax liability was also not paid at the time of filing GSTR-9 of 2017-18. Now, while filing GSTR-9C, we want to pay this liability through DRC-03. How to show it in GSTR-9C?

Also, Is interest also payable on such additional tax liability that would be deposited through DRC-03? And if yes at what rate and for what period?