You can check here the bridge process.
In resume:
BILLING
Charge Out - The cost is reflected in destination type Billing. If it is a Interco billing the info of partner responsible CC and GBU

Charge In - The cost perspective of the Billing receiver GBU

INTERNAL ALLOCATION
Charge Out - The cost is reflected in destination type PL. The cost moves from a GBU at Origin to another GBU in Destination

Charge In - The cost perspective of the Internal Allocation at the receiver GBU

INVENTORY CONSUMPTION
Destination view ignores Origin Flow FI (linked to purchasing of goods) and replaces it by Inventory consumption, using the flow from where it is consumed.

The way to identify this costs in BW, is filtering the cost elements that explain this flow (consumption of spare parts and packaging). See full detail here