WIP calculation error costing by period and different production versions

All,

Ours is S/4 HANA 1809 On premise version,

We have a scenario where we want to post variances monthly on incomplete production order i.e. not in CNF/DLV status(due to long duration of FG in production order) hence done the configuration to calculate WIP at target costs like costing by period. All working as expected

But we are getting WIP calculation errors in the following scenario.

We use one quantity structure(production version), where BOM& Routing used only for Standard costing of the FG

and

We use another quantity structure(production version) in production order with different BOM/Routing

Reason for the above is, in 1st version(FG material version)we procure or subcontract some components and in production order version we do everything inhouse.

When we are running WIP getting the below errors, Can you please suggest some alternative?