I was trying to use the single vert for the first time and I created these objects using the screw modifier. The thing is I am getting some pinching as you can see in the screenshot. 

[![Screenshot][2]][2] 

I tried adding additional vert by using <kbd>ctrl</kbd>+<kbd>R</kbd> but that's changing the silhouette itself. 

So can someone help me with this?

[file][1]



  [1]: https://drive.google.com/file/d/1dWSgv86fAtKHHIyvwFIcmi1tOScgUPjs/view?usp=drive_link
  [2]: https://i.sstatic.net/0sYDf.png "Screenshot"