DTS-HD High Resolution Audio is different from, but complementary to, DTS-HD MA. Both contain a DTS core for backwards compatibility, but DTS-HD High Resolution Audio only adds 96/24 lossy capabilities to the original DTS format. DTS-HD MA adds lossless capabilities to the original DTS format. You wouldn't find both on the same disc, as DTS-HD HRA is only for instances where there isn't enough space for DTS-HD MA.
Blu-ray players are required to be able to decode DTS, but they are not required to be able to decode DTS-HD HRA or DTS-HD MA. Most do anyway, of course. As such, DTS-HD HRA cannot be used as the core of a DTS-HD MA track, because it isn't a mandatory codec (and is meant as a space-conscious alternative to DTS-HD MA).