Hi Quentin,
Sönke and I work together. It is already a while back we had to use Phantom material.
I still got one clip from a shoot with a colorchecker visible.
I downloaded the new version of PCC 3.44 and converted the .cine file to EXR with different settings and compared this to the conversion to EXR with the PCC version from 2017 that I still have.
The latest version of PCC does the same as the old one when the press release claimed the files are actually EXR 2065-1.
In our tests we came and come to the same conclusion. PCC needs to be set to gamma, not to log1 or log2.
The rest of the settings like the actual gamma setting or gain, if the Tone-Mapping has a Curve or you hit reset - this is all ignored when exporting to EXR.
This is the .cine file, converted to EXR (mode gamma), loaded into Nuke as 2065-1, balanced to the grey patch and overlaid with square patches from the above ACEScg colorchecker.
Hope this helps.