Difference in TIFF and RAW import with ACR (how to fix)?

Question

I'm experimenting with a workflow, so whilst this may seem like an odd thing to want to make work, I have a geniune reason for doing what's described below:
I have Canon CR2 RAW files from a 7D, Photoshop CS6 13.01 64bit, with ACR 7.1.0.354, running on Windows 7 64bit.
1. I import a CR2 image via ACR, with no changes to any sliders; opening it as Adobe RGB (1998); 16bit
2. I then save the image as a TIFF file, leaving "ICC Profile: Abode RGB (1998)" selected in the Color section of the file save dialog
3. If I then close all files, and reopen the CR2 and TIFF image, they (as expected) appear to be identical
4. After closing all files again, I then open the CR2 and make an exposure adjustment (e.g. -1.00)
5. Using Bridge, I select the TIFF file, right click and select Open in Camera Raw. I make the same exposure adjustment as for the CR2
6. Now, the adjusted CR2 and adjusted TIFF are different. A colour shift is noticable, and for a severe exposure change (i.e. +4.00) the shadow detail in the CR2 is a lot lighter
Here are two cropped areas from the files (with a 4 stop push), showing some branch/leaf and grass detail respectively. The TIFF has a greener colour cast for the grass, but much darker shadows:
TIFF
RAW
I appreciate that the CR2 is still a RAW file, and as such has the original Bayer pattern data, but is there any way I can make ACR adjustments to a TIFF (taken from a CR2) to behave in the same way as the original CR2?

Answer 1

ssprengel, Jeff, JJMack - thanks for the constructive replies
station_two - after your use of mildly aggressive language ("What seems to escape your grasp") in your first post, I had money that your subsequent response(s) would be on the lines of "I'm too busy to explain it to people like you". Thankyou for confirming my expectations (sometimes I wonder if some people engage in forum discussions for the sole purpose of trying to get themselves [and possibly others] riled)
So... back to trying to find a construcive solution: If the algorthirms for the adjustments in ACR do operate directly on the Bayer data (before demosiacing to RGB per pixel) then operating on the TIFF (or any other demosaiced RGB data) will indeed be a non-starter. Without (probably unlikely) input from an Adobe developer however, we can't know for sure.
> So RAW numbers after debayering to RGB are linear with numbers of photons within a particular color (R, G or B), while TIF numbers are assumed to be linear with human-vision sensitivity
Understood (I'm familiar with gamma, camera sensor behaviour, exposing to the right etc). Ultimately though, it should be possible to produce an RGB file that is also linear (i.e. not adjusted for human vision) to then bring back into ACR. However, if that's simply not possible with ACR, then that's also a non-starter (and wouldn't help anyway if the adjustments operate on the Bayer data directly).
I did look briefly into opening the RAW as a smart object, but sadly I didn't think that'd help. The goal I'm trying to achieve is an experimental idea to blend parts of images together from multiple exposures; but to achieve a single RAW file with that data as if it came from the camera (thus it could be brought into ACR to get the benefit of - from my point of view - the useful and intuitive adjustment sliders). Clearly that would require reverse engineering the particular RAW format for the camera being used (and each and every camera you'd want to support) - thus, it's not really practical.
I'd hoped to be able to convert (without edits) the RAW images into TIFF (or some other lossless RGB container that I can read programmatically), do the blending to produce a single TIFF, and then bring that back into ACR.
Whilst it's more convoluted, I suppose it might be possible to generate the unedited TIFF files purely for the purposes for getting data about the images, then using that to create a set of masks. Then, as Jeff suggests, perform adjustments to the RAW files in ACR, and use the masks to blend the imported (and now corrected) RAWs into one image. Not ideal, but perhaps worthy of more experimentation.