Printing using Proof settings results in very different output from Shop vs ID

Question

Shop and InDesign come out with very different color values using the same settings when printing with Proof Settings.  Anyone know why, or which is correct?  Here's my scenario:
1. In the color settings for both apps I turn off Black Point Compensation, Use Dither and Compensate for Scene referred profiles (some are Shop only obviously).  Other than that it is default settings.
2. I create a CMYK document with 4 squares.  Filled with 100% Cyan,  100% Magenta,  100% Yellow,  and 100% Black respectively.  Setup the Working CMYK in both apps to Coated Forga27.
4. I setup a Custom Proof condition with an ISO Uncoated Yellowish CMYK profile.  Preserve CMYK Numbers and Black point compensation are both unchecked.
5. In the Print engine I set Color Management to Use Proof settings, Color handling done by the application, and leave the Printer profile set to the CMYK working space (Coated Forga27), and Output Color as Composite CMYK in ID.  Black Point compensation is also unchecked here.
6. Now when I print to file and Distill (job settings set to leave color unchanged and compression is off) the resulting files from both apps here is what I get:
InDesign CS4:
Cyan square (C:84 M:14.6 Y:0 K:0 ), Magenta square (C:2.9 M:84.9 Y:14.1 K:0 ), Yellow square (C:0 M:6.2 Y:84.1 K:0 ), Black square (C:67 M:62.75 Y:56.86 K:46.28 )
PhotoShop CS4:
Cyan square (C:92.94 M:12.55 Y:5.49 K:0 ), Magenta square (C:5.49 M:94.51 Y:13.73 K:0 ), Yellow square (C:0 M:5.49 Y:92.94 K:0 ), Black square (C:83.14 M:85.49 Y:78.04 K:98.82 )
Needless to say the results are very different.  I went ahead and did some manual Profile -> Profile conversions in Shop to see what is happening and it seems like Shop is doing a conversion from the Documents assigned CMYK ->Proofing CMYK-> Printer CMYK.  But Shop adds black  point compensation in automatically for the final portion of the color  conversion (Proofing CMYK-> Printer CMYK) even if it is unchecked in the  color settings, Proofing dialog, and the print engine. 
InDesign has an  entirely different way of "using Proof settings".  It seems that if you choose  Use Proof Settings in the print engine it just assigns Proof CMYK to the  document and Converts that to Printer CMYK.  Document CMYK is ignored  completely.  Verified this through manual conversions in Shop as  well.
What gives?  Which do we trust?  To me it sounds like PhotoShop is doing the closest to what I would expect.. except for the addition of the sneaky black point compensation without being told to do so.  Thoughts?
Matt

Answer 1

Before digging too far, I need to understand what you're trying to achieve.
With the print settings you describe you are instructing the application to perform two conversions. The color chain is Document CMYK (FOGRA27) – Proof CMYK (ISO Uncoated) – Document CMYK (FOGRA27).
This is a little odd. Usually the final color space is a print device of some sort, not a press profile. This workflow you describe is a round trip of sorts. We are at FOGRA, convert to ISO, now back to FOGRA. That amounts to simulating one press condition using another press condition, which is rarely done because a press in not a proof device.
The Proof profile is the print condition you want to simulate. The Print profile is the device doing the simulation, which is often referred to as a proofing device (quite confusing but that's the way it is).
Photoshop Proof Setup has a Rendering Intent and BPC. InDesign Proof Setup does not.
In the Photoshop print dialog, there is a Simulate Black Ink option. The InDesign print dialog does not have this option.
There are two conversions on output. In Photoshop output, the first conversion is Document – Proof. The rendering and BPC options for this first conversion are based on Photoshop color settings. The second conversion is Proof - Printer. The Photoshop print dialog offers 3 options for this 2nd conversion:
1. Simulate Black Ink Off = Relative Colorimetric, Black Point Compensation On.
2. Simulate Black Ink On = Relative Colorimetric, Black Point Compensation Off
3. Paper Color On = Absolute Colorimetric
Please note the application color settings do not affect this conversion, just the first.
For the most accurate proof #3 is the best option. That is not saying that absolute colorimetric is ideal for file conversions. It is a rendering intent that is ideal for a proofing workflow, and the conversion to the print device (the 2nd conversion in the output you describe) is what is at the heart of the proofing workflow.