Asset Hierarchy updates to the child assets

Summary:

Asset Hierarchy shows the Parent and child asset hierarchy which can be created based on the Item structure definition or can be created manually. My question is about changes/updates to the child asset with 2 different scenarios

Content (required):

When I have created Hierarchy automatically based on the Item structure definition , the child does not show the replace/delete/add additional child asset under this child asset. but I can do all these when I have created hierarchy manually.

It makes sense that since the hierarchy created from Item structure there wont be any further updates. I am in a situation where client wants to create the hierarchy upon sales order shipment based on the Item structure but would like to replace child assets later.