grp.checkwrite and supported datatypes

[npinguin]

Hi

I am updating my scripts to use grp.checkwrite instead of my own wrapper that simply wrote things in memory and then did a string compare to prevent unnecessary bus load

so far I have the following experience
- booleans it seems to work fine

- floats only works fine,  if I add the delta argument at the end for example grp.checkwrite(KNXGROUP, newValue, 1)
but why is this needed ? 
in my opinion it should have a default behaviour if there is a difference then write to the bus

- text does not work fine ? grp.checkwrite(KNXGROUP, newValue, 1)
It always writes the newValue to the bus ? How can I prevent this with grp.checkwrite ?
For now I use my own wrapper again for this

Thanks
Nicky