Color Balance Adj Layer Characteristics Changed from CS4- CS5?

Question

Maybe some guru with better connections to Adobe knows the answer to this. (or maybe I just forgot).
I just discovered (and I don't think it is pilot error) that the characteristic behavior of the Color Balance Adjustment Layer is different in CS5 than it was in CS4/CS3.  (Much stronger in CS4/CS3).
In addition, there is also an associated behavior that is like a buried legacy mode that is not made visible to the user.  Here is what I mean.
If I create an image in CS4  with a single Color Balance Adj Layer, I get an adjusted image.
If I open that same PSD file in CS5, the same image is displayed.
If I use the same base image, yet create the Color Balance Adj Layer from within CS5, the adjusted image is different than the prior two.   So the Color Adjustment Layer acts like it has a hidden legacy mode where the characteristics are one type if created in CS4/CS3 yet a different characteristic if created in CS5.
My mind might be slipping (or my cold has the better of me) because I do not remember this as a documented change and I searched the internet for "What's new in CS5" etc etc.  I don't remember anything on other forums about this either.
I guess the good news is, the new characteristic of the Color Balance Adjustment Layer is better behaved with a transfer curve with less clipping for highlights and shadows.  Very similar to the better behavior of the change of the Brightness/Contrast Adjustment Layer going from CS2 to CS3.
Here are some comparison images.
This is the Layer Stack Used with Base Image of simple B to W gradient with CB Layer on top with just the highlights pegged to red.  This is the exact same Layer Stack for all of the images shown:
Here is the first image.  This was created in PS CS4 and displayed from CS4 with the conditions show above:
This is the same image from above that was saved as PSD with profile and them imported to PS CS5 with same profile.  There was no change:
This next image is using the same base gradient, yet then creating the CB Layer from within PS CS5 with the same parameters, only the Red pegged for the Highlights:
Does someone have an easy answer for this.  Can someone duplicate this and confirm the change from CS4 to CS5.  A test by someone else would either confirm I am off base with pilot error or there is something to this.
And yes, all the images were sRGB and kept in sRGB for creation/display.  All Screenshot images were the images brought up side by side on the same color managed monitor.   All Edit > Color Settings were identical.
Thanks in advance for any help
John

Answer 1

OK, Chris, but before I perform my act of self flaggelation for the benefit for all and my extra embarrassment, let me add in some useful information about the Color Balance Adj Layer that could be helpful.
I was working with another individual who wanted a better understanding the color balance adj layer, what is was exactly doing, how the shadows, midtones, and highlights interacted, and the differences with preserve luminosity checked or not, and also why the preserve luminosity was so hard to predict (e.g. did not really preserve luminoisty).
Without going into the deails of all of that, the tidbit I will leave as far as penance for my stupid original post above is that the Color Balance Adj Layer with the Preserve Luminosity box checked does a reasonable job or preserving luminoisty for the midtone adjustments yet definitely does not for the shadow and highlight adjustments.
An easy workaround for this is to just set the Color Balance Adj Layer Blend to Color which preserves Luminosity of the image presented from lower layers while maintaining the Color as best it can from using the CB Adj Layer  (It holds the Hue and does its best to keep the same Saturation yet the Luminoisty from the presented image from lower layers takes prescendence).  This does a much better job at preserving Luminosity than using the checkbox option.    I usually use this approach and keep the Preserve Luminiosity box turned off.
The error that I made was during the fairly involved exchange with this other individual, at some point I accidentally set the Layer Mask for the CB Adj Layer to 50% gray and did not notice that it had changed from the default white.  Much further down the line, when this other individual could not exactly recreate my results, he mentioned working in CS3. Thinking this odd,  I pulled up CS3, created the image from scratch (without the erroneous mask change to 50% gray) so therefore I duplicated his results and did not realize the error was in my original Layer Stack.  To make a long story short, I went and checked for differences in all system settings, profiles, Color Settings, opacity settings, Blend settings, Layer Style settings (and their options) etc, etc and overlooked a change in the Mask gray level.        When I quickly flashed back and forth between the two documents/stack it finally popped out at me. Mea Culpa.