When service tracking is enabled, time entries will be marked as billable if both the project and the service logged are billable.

You can  adjust whether or not a service is tracked as billable from the service management page.

Set a service as billable

1. Go to the Settings Page in your Time IQ account
2. Scroll down to the “Service Tracking” section.
3. Click the “Manage Services” button
4. Click the service you want to set as billable
5. In the right sidebar, toggle the “Billable?” option to “YES”
6. All future time entries that use this service will now be marked as billable. (Requires that the project logged is billable as well)

You can also adjust the billing rate for your project if you have rate tracking enabled and set to track rates by project.