Exported typelib not getting updated C# project

Question

I am exporting DLL to a typelib(.tlb) using

"C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\RegAsm.exe" $(TargetDir)Project.dll /tlb:com.Project.tlb /codebase

It is getting registered succesfully.I look in typelib using liewiewer,all method declaration was proper.

But if I add any new method in DLL project and rebuild/clean .tlb file seems to be not getting updated with newely added methods.

Please let me know what I am missing?