From watching the video, you observed right Achim's shoulder strap does crowd the inflator port a bit.
I have not researched this and do not know,..., I only am just about to set up my own very first BP&W (just regular, singles for now) but I wonder:
What if the shoulder webbing was attached to the inner BP instead?
Would that violate anything?
Would the upper BP connecting screw be overloaded (shouldn't if it is stainless steel I think, could there be a second one if need be)?
Would the outer plate bend? Doubt it, especially in SS, but even alu.
The lead edge of the wing would not be restrained from folding up by the webbing (less streamlined? ...not sure, if you need the air volume in the wing it will displace water and create drag somewhere...) and your shoulder straps would not go tighter and tighter on you the more you inflate.