Default packaging for an item

Team,

version: 6.3.1

At Packaged Item ID level, there is a field:"Default Packaging" which states that select the check box if this is the default packaging for this item. However during OR creation via UI, system always prompts to enter the packaged item ID. Ideally the user should enter the Item ID and have OTM select the default packaged item ID based on the check box selection- correct? This is not happening not sure where did the simple set up is incorrect.

On the other hand, if the above mentioned field says the default packaging unit for this packaged item, the same also does not happen. Post OR creation, the packaging unit field is empty although I have selected.