I'm still working through the issue of being able to take each item in the flattened bom - and be able to pull the correct total from the Inventory table. So far - I'm getting either ... repeating rows, or inflated totals.
It's like I need to join the query I have working which only flattens the bill of material - and adds up all the amounts of each component required (the original CTE / recursion query) - and then query the Inventory table.