Actually that is incorrect.
![Er... what? o_O o_O](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
If you have a Dts:X track then it is down mixed to Dts HDMA before being upmixed by DSU. Atmos remains unchanged.
![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Bring up the info button and you will see. I thought it was fine too but I don't think this is a recent change.
Atmos/Dts:X should use "Straight" upmixing is of no benefit.