As far as it is known, IQAS and ICES solely acknowledge degrees from Sikkim Manipal University. For ECA you should opt for Sikkim Manipal University but do not go for WES as they do not recognize degrees from SMU. 

It is suggested that you opt for IQAS as they take 5 – 6 weeks for the fulfillment of the process accurately whereas ICES generally takes around 25 weeks for the completion of the same.

You may check the site of Degree Equivalency Tool for any further queries.