Neither of these modes to start is anywhere near averaging 6500K. Both also move further toward red as the image gets darker. Fortunately, the Color management system and the gray scale controls work well. Or, as Mike put it:
Grayscale calibrated reasonably well, with only a bump at 100 IRE (to 7.5) detracting from a very good average Delta E of only 1.0 from 20 to 90 IRE. The RGB balance was also good and other than the bump in red at 100 IRE, was consistent across the whole IRE range. The RGB controls worked like they’re supposed to, with adjustments to Gain and Bias only having small effects on each other.
Gamma has a number of available adjustments that allow you to get a good average. However, I had to adjust the Film gamma from its default (which should be around 2.2) to 2.5 to get a 2.2 average. This results in an average of 2.18, but is not consistent across the range.
Per one of Mike's charts (on the advanced calibration page for our subscribers), the gamma quickly lowers in number as one moves up from 80 IRE. As a result there's a high gamma in the dark scenes, adding to the richness, but also making them seem a little darker, while very bright scenes are more "TV" like than movie.
Bottom line on the Gamma, the final number looks really good, but the gamma isn't consistent as it should be, across the range.