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If you want to know more about the way we calculate time please check out How time spent is calculated (with working hours)?
Is it compatible with Tempo?
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When working on a sub-task time spent is reported only on the sub-task. Parent issue is not updated so you should not keep the sub-task and the parent issue in progress at the same time.
How to see Organizations on the timesheet?
See Break down time by Organizations from Jira Service Management