That's a deal breaker for me in that case.
Using the colour sampler in ACR (combined with the Adjust and Calibrate tabs), I can get the bottom two rows of the Gretag CC to almost their exact 16bit (in my case) values. A final tweak using Curves and Hue/Sat in CS2 completes the job.
In fact, if ACR had the same fully speced H/S as CS2, as in a Lightness channel and a drop down menu containing ALL of the colours in the third row of the CC, then I wouldn't need CS2 at all for colour correction.
I shoot mostly fine art for museum catalogue reproduction. Digital has given me colour I could never have dreamt of using film. More importantly, it has given me colour control I never had.
While I would happily seek out the % equivalents of the 16bit values I am aiming for, not being able to sample them on the CC is a seriously retrograde step for me. Useless, in fact.
As things stand, CS2 is half baked in that it permits only 4 samples (compared with nine in ACR), while ACR has a half baked H/S feature.
But, Lightroom, from my perspective, is a serious dumbing down. As the late lamented Fraser wrote (and I'm paraphrasing), "...if you know the numebers you're aiming for, you can correct on a black and white monitor." I'm pretty much at the point with ACR. LR doesn't even come close.
I, for one, won't be buying it.
Thanks again for your help.