> ## Documentation Index > Fetch the complete documentation index at: https://www.plain.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # How SLA time is counted > How an SLA target counts business hours, and what happens to a running deadline when you change hours, add an override, or pause the thread. An SLA target is an amount of working time, such as 4 business hours to send a first reply. When the target uses [business hours](https://www.plain.com/docs/product/platform/business-hours.md), only time while its schedules are open counts. The deadline Plain shows is the moment that working time runs out, under the hours as they stand now. This applies to [SLA policies](https://www.plain.com/docs/product/platform/slas.md) and [tier SLAs](https://www.plain.com/docs/product/platform/slas/tier-slas.md) alike. ## The rules Every change to hours or targets follows these rules: * **The amount of time is fixed when the clock starts.** Editing a target's time affects clocks that start after you save. A clock already running keeps the amount it started with * **The hours decide when that time runs.** Time counts while any of the target's schedules is open, with each schedule's overrides applied. A target with no schedules counts 24/7 * **Time already counted stays counted.** No change to hours, overrides, or schedules adds back time a target has used, or takes away time it hasn't * **Time left follows the current hours.** When the hours change, for example you edit a schedule's weekly hours or add an override, a running deadline moves to match. Closing time pushes it later. Opening time, such as deleting an override that closed a day, brings it earlier * **Finished targets are final.** **Achieved**, **Breached**, and **Canceled** targets aren't updated by later changes ## Which hours a target counts A target counts time whenever at least one of its schedules is open. Each schedule applies its own overrides before the schedules are combined, so an override only closes the schedule it belongs to. An SLA on a London schedule and a New York schedule, with London closed for a bank holiday, keeps counting during New York's hours that day. Close both schedules with an override each to stop the target counting. A schedule with no weekly hours counts as no schedule at all, and its overrides don't apply. If every schedule a target uses has no weekly hours, the target counts 24/7. ## When business hours change These changes move the deadline of every target counting down on the schedules involved: * Editing a schedule's weekly hours or timezone * Adding, editing, or deleting an override * Changing which schedules a target uses, or switching a target between business hours and 24/7 At the moment of the change, Plain keeps the time the target has used and counts the time it has left against the new hours. ### Example: an early close A team is open Mon–Fri 09:00–17:00 and has a 4 hour first response target. A thread arrives on Monday at 09:00, so the reply is due at 13:00. At 10:00, an admin adds an override that closes today at 12:00. The target has used 1 hour and has 3 left: 2 run until 12:00, and the last runs from 09:00 on Tuesday. The deadline moves to Tuesday 10:00. ### Targets past their deadline A target that is **Breaching** stays **Breaching**, even if a change adds closed time before its deadline. A target that already sent its **Imminent breach** warning stays in that state if its deadline moves later, and Plain doesn't send the warning a second time. ### Hours for time that has passed Editing hours for time that has already gone by, including earlier today, doesn't change what any target has counted. That includes editing or deleting an override whose dates have passed. The same applies when a target starts after its clock should have. For example, a workflow applies a policy an hour after the thread arrived. The first response clock still starts at the thread's arrival, and that hour counts under the hours as they stand when the target starts. ## When a target pauses Resolution time targets can pause while the thread is in selected statuses, such as **Waiting for customer**. See [Pausing resolution time targets](https://www.plain.com/docs/product/platform/slas.md#pausing-resolution-time-targets). At the pause, Plain holds the exact time left, and changes to the hours don't affect it while it's paused. When the thread leaves the paused status, that time runs from the moment it resumes, under the hours at that moment. A target that resumes while every schedule is closed starts counting when the next one opens. Response time targets don't pause. They cancel or keep running as described in [Snoozed threads](https://www.plain.com/docs/product/platform/slas.md#snoozed-threads). ## What each change does | Change | Time already counted | Time left | | - | - | - | | Weekly hours edited, or an override added, edited, or deleted | Unchanged | Counted against the new hours from the moment of the change | | Schedules on the target changed | Unchanged | Counted against the target's new schedules from the moment of the change | | Target's time edited, for example 2 hours to 1 hour | Unchanged | Unchanged. New clocks use the new time | | Thread moved to another SLA | The old targets are canceled | New targets start, measured from the same start as the old ones | This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.