The imperial 1/32" step sizes is just under 0.8mm step sizes. You would need metric 0.5mm for finer steps...
Perhaps grip strength of the collet on something near the bottom of its range is compromised, but unless you buy nearly 50 more collets, 1/32" steps is going to be hard to beat...
Again, maybe I'm missing something...
In my case I have a damaged drain plug in a JD tractor. Someone in a previous life lost the oring in the plug and over tightened it, messing up the wrench flats. 12mm bolt, with 19mm hex. I was going to convert it to a 18mm head, but lacked a way to hold it in the 5c blocks. So, that was the proverbial straw, that triggered the purchase...