For my three cents:

I have always considered that VH depreciation can only be deducted against rental income, so the income from the sale doesn't allow* it;

At the point of sale, since it is not allowed*, and the adjustment to basis is only for depreciation "allowed* or allowable*," I will not adjust the basis for it.

Effectively, since most, if not all, VH Schedules E defer the depreciation, NONE of it is ever allowed. How you get it to work that way on software is unknown to me.

I have no research to back this up, just my logic.