If you skip down a couple of paragraphs (actually it is good reading so don’t skip the good stuff) it talks about the advantage of the process approach providing control over the linkage between the individual processes. This one may need to be read a couple of times to make any sense.
Here is another way of looking at it. An auditor once told me 90% of his findings came not from the processes but from the hand off between processes. In other words, mistakes came from poor communications and lack of ownership. This is the place the quality manager needs to be most vigilant. No one else is going to be looking at these because no one has clear ownership. If you’ve ever spent even a few minutes on material from Dr. Deming or Dr. Juran you’ll understand how this creates failure.
I was doing an initial audit on a new client and following an order that was in manufacturing and due to ship the next week. There was a discrepancy between the purchase order revision of the print and the manufacturing documentation. In engineering I found the order had been returned to sales because the revision required a significant tooling investment on a product that engineering understood was being phased out. As far as Engineering knew Sales was handling the situation. As far as Sales knew, the product was in production. The problem was no system for communicating print issues back to the customer. Engineering wasn’t responsible and Sales wasn’t responsible so no one addressed the issue.
Want to find the points in the system most likely to fail? Sketch the process from customer through your company and back to the customer. Circle points of hand off between departments. Check how this flows if things are working and how the flow of communication works when something goes wrong. Pay particular attention to who is responsible for what actions. Now quiz people and see if they are aware of their responsibilities.