Please try Channel Type Dimmer (!) instead of Number. Reason is, Dimmer is of percentType.
If I change to Dimmer I get 40% but I still lose the decimal digits
Type dimmer : humPraesenzTom "Luftfeuchte Präsenzmelder Tom" [ position="9.007:<11/3/20" ]
Dimmer humTestTom "Luftfeuchte [%.3f %%]" {channel="knx:device:bridge:backbone:humidity:humPraesenzTom"}
I wouldn’t even mind getting a number instead of percent as long as the precision is preserved.
I found a workaround but it is really ugly:
After changing the dpt from 9.007 to 9.001 I now get the desired result with
Number:dimensionless [%.2f %%]