I assume that since they talk a lot about hearing loss in the SENS-401 release, it might have the same role in the hearing part as SENS-218 had in the vestibular part, while still being useful in the vestibular part. But a different mechanism might be involved, that's true !
Quotes :
"Preliminary results  from the preclinical studies with  SENS - 401  in hearing loss resulting from acoustic trauma will  be  presented  at  the 46 th Annual  Meeting  of  the Society  for  Neuroscience  (SfN),  Neuroscience  2016, which will be held on November 12 - 16 , 2016 in San Di e go, California."
or
"Sensorion  has  decided  to  select SENS - 401 ,  instead  of 218 , as  its  final  drug  candidate for treating  lesions of the inner ear" > "lesions of inner ear" could cover quite a large area...
@Stakovic on their website, they seem concerned about : vertigo, hearing loss, tinnitus and ototoxicity.
So in their pipeline is :
- SENS-111 (vertigo)
- SENS -300 (ototoxicity)
- SENS-218 now replaced by SENS-401 (vestibular and auditory lesions)