An Audiologist, by nature of their extensive study and residency, should not have to take the HAD licensure exam to hold dual certification both as am Audiologist and as a hearing aid dispenser.  It is by the advanced training that the Audiologist has the knowledge and credentials to dispense.  The dual certification adds nothing to the skill set the Audioliogist already posseses and it does not provide any addtional benefit to the population served.