Just sharing a code snippet. This python3 script uses the Epicor 10.2 REST API to build a proper BOM.
https://bitbucket.org/fievelm/workspace/snippets/6XEn4p
It does have some dependencies, will have to pip install treelib and requests.
I thought others might find it useful, so I ripped the relevant parts out of my existing project. With JS/CSS you can make a web based BOM that looks decent.
Attached are example output screenshots