Can developer design model be reused for generating test cases

When there is a plan to adopt Model Based Testing, generally people think of reusing product design model. Product design is for developers to implement requirements that contains low level design. The purpose of

product design is to break down the requirements into smaller tasks and for each task; corresponding class is defined to implement its responsibilities.

Now, before we think of reusing the model, we need to define the scope for adopting model based testing. If MBT is planned to generate test cases for developer testing (white box testing), then it is feasible to reuse product design model.

If the scope is for system testing, then it is not feasible because system testing does not look for class level design. In system testing, scope would be to verify and validate product behavior with respect its requirements; for which, test analyst should create model for system level testing.