If this option is enabled, the build will be added to the queue at the specified time, with a delay not more than a minute to reach second precision in scheduling. This mode has the advantage that the build is guaranteed to happen, even when a build with the same parameters is triggered. By default, Jenkins will deduplicate builds with same parameters, and only one of them will be executed. This will also set a dedicated cause for the build, so it is clear why the build was triggered.

If disabled, the build will be added to the queue immediately. This mode has higher visibility, but there is no guarantee that the build will actually run at the scheduled time. If another build with the same parameters is triggered without delay, Jenkins will deduplicate the builds and only the one that starts next will be executed.