It absolutely should regenerate them, although it may require repeat dosing in areas where support cells are more intensely depleted.
The math of support cell —> support cell + active hair cell is imperfect. All we have to go off of is their presentations and the patent source provided by
@Diesel.
In my case, it'd be most advantageous for the math to be closer to a 1:1 ratio. For the health of more of the sufferers on this board, it would be more favorable for it to first bolster the support cell population before newer generations of HC's can be induced to create active HC's. I hope, and actually believe the case will be the latter. I want more people to be helped than just the preferential few with abundant SC populations. I wouldn't mind at all undergoing this procedure two or three times for it to do what it needs to do.
I would find it odd if it were to preferentially restore IHC's considering their quote of 15k hair cells, which refers to the OHC population, with no mention of IHC's (although that other presentation seems to depict IHC restoration as well).