Data Collector

Hello,

I'm setting up some data entry profiles.
I already got one sub step where it always ads 1 like this: value(Source('TestNumber'))+1
(3 Pocket Penetrometer Readings )
For a different sub step I need the action for 'Depth Top' (m) like this: value(Source('Depth Top'))+0.1.
It's about the 'Dynamic Probe Tests' and the driller needs to note every 0,1m starting at 0,1m, but I don't want him to write all Depths from 0,1m to 16m in decimeter steps.
The default value 0,10 works fine.
But the action does not.
I already tried with just adding 1 instead of 0,1.
Of course I'm not using ',' as decimal separator in OpenGround.
Do I need to use other expressions? (Other question: Is there maybe anywhere a list with all expressions for OpenGround?)
Are Depth related column excluded from 'actions'?

Would be nice, if someone could help, thanks! :)