Orchestration process assignment

Summary

Orchestration process assignment on Fulfillment line

Content

Hi,

We have created the item which can be used as bill only item. As standard orchestration processes i can see bill only generic process is also there and normal DOO Generic process is there. in "DOOFulfillment generic process" we have seen- Stock, Back to Back and Drop ship flow configered. 

But when i create an order with the item for which bill only process should be assigned. i can still see the "DOOFulfillment generic process" though line status is going in awaiting billing. I would like to know how this assignment is happening.