HB & non dependants

Good afternoon
I have a family who have moved into a property through the assylum resetlement scheme (classed as TA hence the HB).  They are a brother and sister and their mother - The tenacy is in the names of the brother and sister.  Each family member has a UC claim, the brother and sister have both been awarded HB however, the non dependant charge of £19.30 has been applied to both HB claims effectively making the non dep deduction £38.60.  Should it not have been applied to each claim at 50% so the dedution is only £19.30?
Many Thanks

Yes
See HB Reg 74(5)

(5) Where a person is a non-dependant in respect of more than one joint occupier of a dwelling (except where the joint occupiers are a couple or members of a polygamous marriage), the deduction in respect of that non-dependant shall be apportioned between the joint occupiers (the amount so apportioned being rounded to
the nearest penny) having regard to the number of joint occupiers and the proportion of the payments in respect of the dwelling payable by each of them.

Thanks so much for your reply, I have challenged the decision.