I have a question on tool length probing. Is that for Lcvette ? 

Could you give me an overview on how it's *supposed* to work please?

What I see now is that the tool length discovered seems to change depending on where I set the current work offset Z? So for example if I zero the Z at say machine zero, then do a tool offset I get some tool length. Then if I rezero and measure again then my work offset Z gets adjusted again. Zero again and repeat and I've got another offset. Etc

My expectation might be that the tool length reads off the machine Z and not the work offset Z?

For reference my machine doesn't have tool holders, just a collet. So I would need to measure after every change anyway