SOLUTION FOUND!!! TESTED ON MULTIPLE TVS!!!
I too was struggling with the +/- volume instead of the numbers for my soundbar. After some research and multiple calls to Samsung I actually figured it out on my own. Regardless of what audio output source you are using (hdmi, optical) the TV needs to be paired via blueooth in order to get the numbers to show. Optical and HD I only carry information away from the TV and therefore cannot tell the TV what volume the soundbar is set to. And unfortunately if you pair it afterwards it doesn't recognize what's going on. Follow these steps and you'll get your numbers on screen.
Step 1. Unplug all audio sources from the soundbar.
Step 2. Reset your soundbar
Step 3. In TV sound setting Unpair your soundbar.
Step 4. In tv settings reset audio settings.
Step 5. Put soundbar into Bluetooth pairing mode
Step 6. Scan and pair your soundbar
NOW YOU'LL SEE THE VOLUME NUMBERS
Step 7. Plug in your preferred audio source
Step 8. In tv sound setting switch to your audio source. The TV will now use your audio source to supply information to the soundbar and the soundbar will still use Bluetooth to send the audio volume information to the TV
