Export VR film from stereoscopic to monoscopic ? Not working

In the export settings window, I scroll down, check the box that says video is VR, then select monoscopic ( is original stereoscopic) in the frame layout. I still get stereo results. No matter what numbers I put in the Frame size or Horizontal Vertical field of view. Any one can help? Thx! #vr #stereoscopic #monoscopic #export