Positions provide you with a finer degree of structural definition and control than organizations on their own. You can use both organizations and positions to represent your reporting structures. However, if you define both, you must also maintain both over time. This may lead you into duplication of effort and information.
Suggestion: If you decide to use positions to represent how people work in your enterprise, it is best to define most of the detail at the level of the position. Do not duplicate this detail in organization structures.
Use organizations to show your highest level of departments or divisions. Use positions and position hierarchies to show the reporting groups existing in your enterprise.