Facing problem in multi - level variant configuration

[MK12]

We are implementing AVC Advanced variant configuration in Flexible Packaging Industry in which we have finished materials based on different structures. In Current example, FERT is combination of three films for example, FERT = PET + MPET + PE. I have assigned Class type 300 to FERT. There is also HALB material in BOM which is also configurable. So, I have defined four Class items in BOM. First three class items with 200 Class & last one with 300 Class for HALB

There are three (200 Type) Class defined. Each PET, MPET, PE materials have 200 Class assigned with characteristics MICRONS & DECAL along with values. For e.g., 

PET1 = 12 MICRONS, 915 DECAL

PET2 = 14 MICRONS, 920 DECAL

PET3 = 16 MICRONS, 915 DECAL

MPET1 = 14 MICRONS, 920 DECAL

MPET2 = 16 MICRONS, 915 DECAL

MPET3 = 20 MICRONS, 920 DECAL

PE1 = 14 MICRONS, 915 DECAL

PE2 = 16 MICRONS, 920 DECAL

PE3 = 20 MICRONS, 915 DECAL

As mentioned, I have defined FERT material with 300 Class and defined class characteristics for 300 accordingly to pick PET components, MPET Components & PE Components. Characteristics used in 200 classes are grouped into 300 Class.

I’m using Class Item K with 200 Class for PET, MPET AND PE in FERT BOM to pick relevant components and it's working fine.

PROBLEM: 

In the First level BOM of FERT, I am using three class types with (200) for components and one Class item K with Class 300 for Semi Finished (Configurable). It means I have further configurable material in First level BOM which i can say It's MULTI - LEVEL Variant Configuration.

Semi-Finished Configurable Material Structure is PET + BOPP + PE. It means in BOM of HALB we are using Three classes i.e., PET (200), BOPP (200) and PE (200). We are using two classes of type (300) i.e., One for FERT & One for HALB. Characteristics of “PET” & “PE” are common in both classes (300), but values can be different for FERT & HALB. We want to configure semi-finished independently, as PET Microns & Decal used for FERT can be different than Semi Finished BOM.

Upon Configuration of SEMI FINISHED, Material is being replaced with Class and unable to retain semi-finished materials.

Please tell why system is behaving like this, why material is being replaced with Class later on. Earlier material is coming correctly but when we configure SEMI Finish it is being replaced with Class.

Please see attachments

[MK12]

Dear Experts, Waiting for the reply