Hello LV
If I understand correct , your finish goods (X) is in you Plant level, your compoenent is in 2 MRP area ( B, C) , there is a BOM in between. to control the precentage. X- ROH ( B) , X- ROH (C)
In this case, system should be the right behaviour that you can only see the requirement in the MRP area level for your component, and in Plant level you can see the Finish goods demand.
However, you want to see your component in the plant level.
You need create Location Hierarchy, for you Plant A as level 1, and assign B and C to that as level 2.
After your planning run in the lowest level (MRP area), you can run SNP aggregation for your component demand and supply in MRP area to Plant A for reviewing.
I didn’t test that, let me know if it works.
I would suggest you keep as is since it’s the standard behaviour , if it is only viewing issue, you can select both MRP area in SNP for viewing.
Hope it helps,
Cheers James.