See also https://forum.rme-audio.de/viewtopic.php?id=38815

TMFX v 1.93 MacOS (3)
RME Thunderbolt Settings Firmware: v112, Driver: v1.05
Fireface UFX+ (23919669) (the old hardware version, I guess: SW Version: 55, Active Nodes: 105

If you turn the Auto Level Max Gain dial, which has a range from 0 to 18 dB, and which can be set in 0,5 dB steps in TotalMix FX, you receive all 37 different values over OSC.
If you send the same values back over OSC, you can only select the Auto Level Max Gain in 1 dB steps (though it will respond to al the 37 different values you send to TM FX via OSC).

Unfortunately it is not some sort of rounding that happens to the resulting dB value in TM FX.
For instance: 3 dB can be set with 3 different values (0.138889, 0.166667, 0.194444) , 5 dB with 2 values (0.25, 0.277778), and 2 dB with only 1 value (0.055556) (as it should be).
But, for instance, setting 3,5 dB is impossible.
The fact that TM FX can send the values, means that TM FX should be able to receive them as well.

Let me know if you can confirm this behavior.

Best regards,

Arthur Sauer