I'm assuming that the reason for the two sets of flowers being different colors is that they change over time, like so many other kinds of flowers do. (The lighter-colored ones do seem a little more beaten-up than the darker blooms.)
Another explanation is that the darker ones are just in shadow, or that my camera is making up colors again, as it often does when photographic subjects are at the extreme red or violet ends of the spectrum. Either way.
Miltoniopsis blooms are nice, but the ones at the orchid show always seem to be basically the same flower -- red or magenta, with varying degrees of spots and stripes near the lip -- with one yellow exception (Miltoniopsis Andrea West).
More typical: Keiko Komoda (from the 2010 show), Morris Chestnut (2010), Arnold Linsman (2011), Lennart Karl Gottling (2012), Echo Bay 'Midnight Tears' (2013, Echo Bay (2013). Surprisingly, most of the ones that come up in an image search are white, which I think I like better than the red / magenta? Not sure.