Items BOM full indented

I have been told that you cannot see full indented BOMs in EPDM under some circumstances in Items. If you create Assembly item 123 with child 456 and later link to upper level 000. The parent 000 cannot see below 123. If the structure was created all at one time, then parent 000 can see all levels.

Furthermore if assembly 123 is edited, replace 456 child with 789 child, then parent 000 is not updated, that these BOM's are independent.

Can anyone confirm this. Is there a difference in how BOMs are created using a linking method vs first entry?

How do you create and use Items BOM's?

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