Orchestration rules not working with bill to customer

Summary:

We want to have a different orchestration process for a particular bill to customer. When we give a simple rule as below, it is not working

If Business unit = X,

and bill to customer is not blank

and bill to customer at fulfillment line = ABC

then assign orchestration process = CustomDOO

Else assign orchestration process = DOO

Please let me know if bill to customer does not work in order orchestration assignment rules?