Bugget billing plan-billing doc creation

Hi experts,

For a resential customer that is monthy charged for 50$(BBP) a billing doc. is created with different billing lines.

The tarrif contains differents components: Fixed amount, distirbution cost, transaport cost, energy cost, rental cost, etc..

I see in the billing lines that the 50$ is split between those differents components.

How SAP billing engine breaks this amount into differents small amounts corresponding to those components ?

Can anyone explain how I can debug this when creating the BBP with t-code EA61, in order to follow the creation process ?

Thank in advance,

Tierno