Production Planning Tool & Multi-level BOM - Source Warehouse for Raw Materials

Hello Dear Community,

I wanted to discuss a bit the Production Planning Tool (PPT) when Multi-level BOM (mlBOM) are concerned.

In our production process we typically have 3 level BOMs:

  1. Raw material - Steel Sheets (UOM: Sheet)
  2. Raw material - Steel (UOM: kg)
  3. Intermediate Parts made from steel (UOM: pcs)
  4. Finished Goods (UOM: pcs or Nos)

When using the PPT with mlBOM ERPNext always tries to get to the last level (wants to request 1.Steel Sheets), even though we have the 2.Steel (UOM: kg) in stock.
When not using mlBOM system only uses one level of BOM (only requests the 3.Parts).

ERP system should first check, if we have any of needed 4.Finished Goods, if not, check for 3.Parts, if none then search for 2.Steel (UOM: kg) and lastly if there is none, request 1.Steel Sheets.

In our opinion, ERPNext searches for the materials in wrong Warehouse. Even though we put Default Warehouse: ROZDZIELNIA in Item Master, in BOMs, in Manufacturing and Stock settings, ERP searches for the materials in 4.Finished Goods warehouse. We have a big stock of 2)Steel (UOM: kg) in ROZDZIELNIA, and still ERPNext wants to get to 1)Steel Sheets)

Can you please guide me?