Powerpoint on iPad connected to external monitor does not fill screen.

Much of what I read leads me to believe this is a limitation. This is a current gen iPad running Powerpoint 360. Slides are 16 x 9 and PPT is set to this, but the image on the external monitor does not fill the screen. About a 10 percent black border appears all around. When run on a laptop, it fills the second screen as it should.

Is this just an unfortunate limitation? Or am I missing something.