On my avr it will state Dolby True HD when that is playing, with the movie dsp engaged.
However, DTSHDMA is only displayed when the dsp is off. So I'm guessing that when I play a br with DTSHDMA, the amp is perhaps not giving me the HDMA. And yet, the player tells me it is outputting it.
I'm guessing the dts-pcm conversion is outputting the full hdma as lossless over pcm.
Like I said earlier, I cannot commit to a preference, I just note a slight 'difference'.
Perhaps the nod might go to the pcm version, because I did notice more detail (a deeper more realistic bass drum sound) when pcm was output. But I can't swear that it wasn't supposed to sound 'worse' :0)