In that case it would appear to be unavoidable. However, when comparing the costs between offices I think it is important to take lost productivity in to account.

When looking at $cost_of_office_with_private_space versus $cost_of_open_plan_office it might make sense to go for the open plan office.

But $cost_of_office_with_private_space versus ($cost_of_open_plan_office + $productivity_cost) might lead to a different conclusion.