That is not possible. unless you are not playing with the right source that plays correctly to the specific channel. Else there is a significant difference from -6 to +6 for the said channels. Also it depends on which profile you are on. If you are on Standard Profile, you wont be able to adjust Wide and Rear Side, or should I said even if you adjust you wont hear any difference because those channels are not in use when using Standard mode. Only in Adaptive / Surround mode is where the soundbar will upmix and that will activate the 2 said channels. But the Wide channel is also working when in Standard mode representing side speakers, again you need to play a source that actually output to that channel to hear sound from it.
On a side note if you are on the right profile and 100% sure your source is actually a real multi channel source, next you might want to be sure the issue of not hearing volume difference is not your own hearing problem. This is by no mean an attack or anything but everyone do have different hearing ability. I can confirm to you mine works at least not based on just what I hear, but also validated with SPL meter. If really you confirm everything and they are really not working, you may want to get Samsung to check your bar.
