I'm a bit shocked by this report, but perhaps this is what we should expect, still .....
Many DVD transports currently on the market fail to transmit the exact digital audio data bit-for-bit as it appears on the DVD. Of the DVD transports Benchmark has tested (8 as of this writing), all of them modified high-resolution audio data before sending it to the digital output
http://www.benchmarkmedia.com/discuss/feedback/newsletter/2009/07/1/your-transport-giving-you-all-bits
Not sure if it really matters since they do pass RedBook bit for bit
although they did pass 'Redbook', CD-quality 44-kHz, 16-bit data without modification
and previous DBT testing shows no one can tell the difference from RedBook and the higher resolutions anyhow.
I don't see a point in the hires discs except for their better or less dynamic compression perhaps in which case they would still pass red book.