I had the same problem, and I found the way around that in PPT 2008 was to set the color of the object by using the fill color eye-dropper from the formatting palette. If I set the color numerically or even from a saved swatch, I would have the same trouble that you're having, but by setting the object color by using the eye-dropper to get the color from the text box, it turned out to be the correct color. I used 2011 for a little while and went back to 2008 (because selecting object in a stack has become even more impossible in 2011), so I'm not sure if the eye-dropper is still available in 2011. Hope this helps! Good luck!