Just tried an experiment. Turned off the front speakers (put them on seperate amp for this test) and played Dolby 5.1 and 2.0 (though surround encoded) programmes. Using Dolby there was just a slight murmor coming from the heights. With the Auro 3D setting there were clear sounds from the heights, including vocals. So something is happening, though if it is right or not I don't know.
Will see if I prefer it.
Edit: 5.1 I'm watching now has no dialogue on the front heights, only music and effects. ??