Propel supports managing costs at a manufacturer part level and allows you to roll-up the costs for a BOM based.
You can define supplier splits:
In the example above, Item 310-00378 has two parts on AML, and they want to a 50/50% split.
The overall BOM cost roll-up is based on the Include in Cost Roll-up checkboxes.
Propel also supports multiple cost roll-ups. Instead of a single Cost, you can configure multiple like Prototype and Production or Quoted and Contracted, etc.
Over time, as your BOM changes (BOM items revision or costs change), you can filter the BOM to look back at the BOM "As of" an earlier date to see how costs change over time. For example, if rev A of this item was released on October 1, and at that time BOM Item 200-00208 was at rev A, you can see rev A and the costs associated with rev A of that item on October 1.