Organization Document Set override on Shipping Transactions Ship confirm

We have a Default Ship Cnnfirm Document set assigned to an inventory organization.   The Ship Confirm Rule that is assigned to that organization does not have a document assigned.  Our assumption was that if the Rule had no doc set, that the organization default doc set would be defaulted on the Ship Confirm window.  It looks like the org default is only displaye dot you do not have a ship confirm rule assigned.  I want to clarify if that is expected/correct behavior?   If so, it seems the organization default document set is of limited value.