When a Jira issue from type non-billable is created than it would be good idea to remove the billable hours field from all the views where developer can log their time, something similar as with the Internal issues that you have. The workaround with the accounts is ok for the invoicing but it will be even better if we don't need to make adjustments every month for this non-billable Jira issue types.
Tempo Products | Tempo Timesheets |
Tempo Platform | Cloud |