Information System reports are analysis reports where in all different cost can be displayed.
Seeing cost at order level is detailed one which lower hierarchy people will be interested. For higher hierarchy, it may not require to have Internal material into Spares & Consumables separately.
All Information system reports are designed based on info sets & info structures.
If you want to have cost separately for Internal Materials, then you may need to define new info structure, etc., I never worked on that part. So please have some more links which can explain you about that.