I guess, this means that, this property cannot be overriden by configuration of derived class and must be specified only inside owner class configuration file.
i found that description of that flag for UE4.4.1 has evolved and now its: “Same as above but load config from base class, not subclass.” which is better describe what i want (than version 4.3.0). Nice to see that such things like comments in code evolving too.