Hello Michal,
I am not a technical person, Parameter EXTENSION_IN
This is an extension parameter that can be used within the SAP enhancement concept for BAPIs. It allows you to enhance BAPI functions without having to make modifications. The extension parameters are always evaluated in the BAdIs intended for this purpose.
could you please check BAdi APO_BAPI_BUS10001 method like CHANGE_SAVEMULTIPLE2 just refer example from SAP note 2046395 - BAPI_PRDSRVAPS_SAVEMULTI2: Fields cannot be maintained for location product
Best Regards,
R.Brahmankar