"Fixed output asyncrhonous mode" vs. "bit-perfect asyncrhonous mode"

[Paperman]

I'm testing my new LE 200 with a simple set-up: only devialet + speakers (and turntable of course).
The streaming is in wifi mode from a iMac with Roon Server software installed.
When I play the files on my library the signal path shows  the following informations:

files from 44.1khz to 96khz: "bit-perfect asynchronous mode" (see pics)

files over 176.5khz and over (also for DSD converted): "Fixed output asynchronous mode" (see pics)

something's wrong? why the highest quality files are not bit-perfect? Do I have to change something for better configuration?
Thank you, Alberto.