My point isn't to belittle anyone or shift the blame on this. The fact it took about five years and someone else's aircraft going for a swim to realize that A + B != C where raft capacity was concerned
The buck obviously stops with the guys whose signatures are on the ECO.
That said, safety isn't any one person's responsibility -- it's shared by everyone who touches the aircraft, and that responsibility never stops.
That includes those who wrote the ECO, those who reviewed and approved the drawings (including the FAA), those who updated the manuals, and yes, those who are supposed to read and apply what's written in the manuals.
WCS and IORFA... if you see something that has an impact on you being able to do your job correctly, but you don't report it, who will??? It might not be in your job description, but if you see something and don't question it, that's just as bad as the guys who f*d things up to begin with.
About eight to ten years ago, AA put out a revision to the briefing cards for one of the fleets (I forget which one...). Four days after they were provisioned on the aircraft, a FA noticed that they didn't show the exit path lighting correctly. We had to destroy about 50,000 briefing cards as a result... They'd been reviewed by Cabin Safety, Cabin Service, and Flight Service multiple times before being sent to the printers. Yet it took a line FA to notice that it was wrong...
Thousands of FAs who read that manual page put blind faith in what was written, and never did the math.... If something this big can be overlooked, what else might not be done correctly?