I've been playing around with the different forms of tone curves and their application through the DNG:PE / ACR / LR chain and have run across something which I can't explain. As I understand the documentation and subsequent discussions here, the tone curve as defined in the PE is what will result when ACR / LR processes with the default values (0 blacks as exception). If I redraw the 'base curve' however (using a 5 point match to make it nearly identical) and then set the base to 'Linear', my result is considerably brighter than with the actual base curve. Assuming that these are being applied overtop one another, order shouldn't matter, and so I am left wondering why my result is so different?
Also, does changing the per-camera default settings in ACR / LR affect the target defaults coming out of the PE, or will they always assume the shipping default settings?