Question ARC and eARC - audio pathway

[Loup Garou]

I originally planned to connect my 4K Blu-ray player and Sky Q box via HDMI into the soundbar and then take the HDMI-out to the TV. Since both the TV and soundbar have eARC functionality, I assumed that this would work. But the installer, who is coming into do the job next week, insists that ARC and eARC will only work if the audio emitting devices are connected directly to the TV and will not work if we 'go through' the soundbar as I proposed.

I found that hard to believe and request clarification from here.