Fixed quantity on BOM not calculating correctly in Costing

Hi All,

I have an issue with scaling materials on a BOM. There are 2 materials on the BOM for material A. One of these (material B) is dependent on quantity of material A produced, the other (material C) is fixed.

Current config in BOM for material A:

Material A base quantity: 1kg

Material B quantity on BOM: 1kg (not fixed)

Material C quantity on BOM: 1 EA (fixed)

Ideally what I want is for each kg of material A produced, use 1 kg of material B and use 1 EA of material C per batch regardless of material A quantity.

E.g. Desired result:

To produce 50kg of material A, use 50kg of material B and 1 EA of material C

To produce 200kg of material A, use 200kg of material B and 1 EA of material C

I have ticked the "Fixed Quantity" field for material C in the BOM, however when I run costing it seems to still be scaling up material C despite the "Fixed Quantity" field being ticked.

Can anyone help? Is there additional fields to be populated to get the desired result?

Thanks,

Michael