Issues with requisition deliver-to location LOV and defaulting

Summary:

We have two issues with purchase requisition deliver-to locations:

1. Locations are availble for selection in the deliver-to field that are not valid ship-to locations. Using Manage Locations setup (Shipping Details section), I have disabled these locations as ship-to site, receiving site, and bill-to site, as well as specifying the desired ship-to location, but they are sill available for users to select on requisitions. Is there some other way to disable a location for selection in this field?
2. When a preparer changes the requester for a requisition line, the deliver-to location is populated by the requester's work location from their HCM record, even if a different location has been saved in the requester's procurement preferences (and even if the location is not enabled as a ship-to site, as described in 1. above). If this same requester prepares a requisition for himself, his preferred deliver-to location populates the req line deliver-to field. If another preparer enters a line with the aforementioned person as requester, the preference is ignored.