Hi Abha,
Thank you for your interest in Syncfusion products.
I am able to reproduce the problem of ‘formulas are not calculated after adding data’. You can work around this by calculating the Excel sheet programmatically using integrated Calculate Engine. I have placed the sample in the link below.
sample-64069450.zipAlso, you can check the documentation in the following link for working with Calculate Engine:
http://help.syncfusion.com/ug_83/Reporting/XlsIO/ASP.NET/Documents/calculationengine.htmPlease let us know if you have any questions.
regards
zakeer Ahamed.s