This methodology supports hierarchical specification of interfaces and their behaviors as :
Each higher level in this hierarchy allows more powerful specifications of behavior. Depending on the need, a particular level of specification can be chosen. For example, if the goal of specifications is to do sequence testing, then enables/disables specification (possibly along with some other state-based specification) can be used. Similarly, if the goal is to do reasoning, the return value specifications and/or trace simplification rules may also be needed.
Specifications can be developed in a top-down fashion for new systems as well as in a bottom-up manner for existing systems using this methodology.