A softproof wish...if only...

Something that occurred to me while adjusting a softproofed image: You know how useful the info panel and color sampler tool are in showing in numbers what the change will be as a result of use of curves, levels, saturation, etc. Well, wouldn't it be nice to be able to quantify the changes that occur when yo "Ctrl-Y" back and forth, so that you could adjust levels or colors precisely. For example, to compensate for a paper that needs a small color balance adjustment? Sometimes when doing it by eyeball, even with the original image side by side, I begin to lose the ability after a frustrating adjustment attempt, to judge how far off I still am. It would really be nice to be able to click on a levels or curves adjustment layer with the gray eyedropper and neutralize the grays with color proofing on, the same way you can without the proofing on.

I don't know if assigning or converting a copy of the image to the paper profile as a trial to adjust would work and give me the numbers, but I wonder if there would be any way for the Photoshop gurus to add such a feature to the softproofing routine.