Here are seven things everyone should understand about package configurations:
Using one configuration file (resident configuration) per server is optimal.
You can apply more than one configuration to a package.
You can apply one configuration to more than one package (this is how resident configurations work).
Each package configuration is applied in the order shown in the Package Configurations Organizer—except Parent Package Configurations, which are applied at execution time.
If an entry in a configuration fails, it will only emit a warning. Configurations should never raise an error or cause a package load to fail.
You can explicitly set a configuration's location in the package or you can point to it from an environment variable.
Configurations are applied at load time, not execution time. So changing a configuration in the designer and then executing the package without reloading it won't apply the configuration. You must reload the package.