1.The re-use of global templates and other components across multiple SPSs, the main advantages of which are single-source editing and consistency of output.
2.SPSs to be modularized, and thus to be more flexibly structured.
In any given SPS, one or more SPSs can be added as modules. Some types of components (or objects) in these modules are then available to the importing (or referring) SPS.
The section, Available Module Objects, not only describes the extent to which, and conditions under which, the various components of an SPS are available to an importing SPS. It also lists those components that are not available to the importing SPS. You should note that if an added module itself contains modules, then these are added recursively to the referring SPS. In this way, modularization can be extended to several levels and across a broad design structure.
How to create and work with a modular SPS is described in the section, Creating a Modular SPS.