On Tue, 27 Dec 2016 10:42:55 -0800 (PST),
wrote:

Changing the picture mode from factory
(Dynamic or Vivid) to Cinema or Movie
will drop your flat's energy consumption
even more, and give you more accurate
picture and last longer.

That may be why the bedroom (smart) TV uses less current. It is set to
movie or something (the lower intensity setting)
The big one in the kids room is still at factory default I suppose.