Oh ok. So Netflix shows with UltraHD tag is SDR. I thought if I played those with UB820 and Xbox, it comes on as HDR. I could be mistaken. Will check again.
Prefer to have Dynamic Range on and video 4K SDR, so that it is is SDR when in any other menu. Save lamp life. 
I think those HDR tagged shows is shown as DV in Apple TV. The same shows is tagged as HDR in my Samsung TVs, UB820 and Xbox. Maybe it is just a small bug in Apple TV but it sure feels good seeing the DV logo