I once worked for a company that provided circuit designs and even application notes based upon construction of a single copy of a circuit, generally at the request of a customer. This is fine if the usual disclamers are given. However, that company did not give any disclaimers at all and customers rightfully complained when they designed the circuit into their prototype systems and the circuit did not work properly. It was my job to help customers with these and other problems and most of the time it was a matter of tolerance of passive components. I fully understand that most manufacturers that provide reference circuits today are more careful to be sure that their circuits show their products in the best light, so are much more careful about what they publish, I still have the habit of going through the necessary worst case analysis of a circuit to be as sure as I can that it will do what I expect over all expected conditions. The burden, of course, is on me as I will be the one to "take the heat" if something goes wrong during prototype testing. Everything today has disclaimers and the user must beware.
It may be tempting to just take a reference design and incorporate it into your own system, but I suggest caution is in order, especially when you have no recourse if something goes wrong. Reference designs can certainly speed up the design process and are a valuable tool, but we still need to do our own sanity checks. Treat reference designs as a tool, not as a proven solution to your design task.