For similar items, the BOM and the ROUTE can be the same.

But the actual design required to have one BOM and one ROUTE by released product variant.

The issue with this design is the BOM or ROUTE maintenance in case of design modifications which will impact all the similar items because each BOM and ROUTE will have to be updated manually.

The idea in the item version, instead of created a new BOM or ROUTE is to be able to affect an existing one.

Like that, updating this unique BOM or ROUTE, it will automatically impact all the items with the same BOM or ROUTE.