It seems like your player is down sampling your files. Hugo won't do that and it isn't a cable problem.
If your player could deliver 24/192 the Hugo would play it, and with a bad cable it would be clicking (drop outs) or not play at all. Your files play at 24/96 and that has nothing to do with the Hugo. It plays what it gets if it can play it.. and in your case it does.
Do you have the latest firmware? Seems to be the October 15, 2013 release.
And I would suggest that you send Oppo an e-mail regarding this issue, as there are a lot of settings on this player and it seems easy to get lost in the menu even for experienced people.
I think you are right. I have tried a cheap coaxial cable and it's also down sampling to 48KHz (orange light). I can't find anything in the Oppo 95 manual but I have just found this in the Oppo BDP105d manual and I assume it's the same:
␣ Due to bandwidth limitations, high resolution audio formats such as Dolby Digital Plus, Dolby TrueHD, DTS-HD High Resolution and DTS-HD Master Audio cannot be sent through the coaxial or optical digital audio output. A reduced resolution version of the same audio track will be output instead. To listen to high resolution audio formats in their best quality, please use the HDMI connection if you have a receiver that handles HDMI audio (see page 11) or use the multi-channel analogue outputs if you do not (see page 18).
␣ Due to copyright restrictions, SACD audio cannot be sent through the coaxial or optical digital audio output. To listen to SACDs, please use the HDMI or analogue audio connections.
␣ Due to copyright restrictions and bandwidth limitations, full resolution audio from DVD-Audio discs cannot be sent through the coaxial or optical digital audio output. To listen to DVD- Audio in full resolution, please use the HDMI or analogue audio connections.
So it seems if this is applies to the BDP95 as well, I have to go through analogue (which rules out the Hugo) or HDMI (which would require some kind of digital audio splitter).