Hi,
You can create two Accounting indicators
A1- Warranty
A2- Billable
While creating the service order at the header maintain A1 which will apply for all operations/Components
And for components which you want to Bill the customer, change A1 to A2
In the ODP1 for your Usage maintain only the accounting Indicator A2 which will only trigger the Debit memo request for components which are having A2 and debit memo request is not created for components with A1
hope it is clear
regards,
santosh