That's because I accidentally hit the 6 and not the 7 because the Atmos track is 7.1 so it's 8 channels.
For Fleetwood Mac Rumours the Atmos is:
Channels 8
Audio Channel Layout 7.1
Bit Depth 24
If you listen to it compared to the DVD Audio (now lossless on the bluray) it is a completely different instrumentation/mixing - listen to Songbird in all 3 formats (Atmos, Surround and Stereo) and you will see what I am saying.