docs: Clarify reviewer setting (#6505)

Co-authored-by: caitlinwheeless <caitlin@humansignal.com>

docs/source/guide/project_settings_lse.md

@@ -250,7 +250,11 @@ If enabled, a reviewer can only see tasks to which they've been assigned. Otherw
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-If enabled, a reviewer only sees tasks that have met the **Annotations per task minimum** threshold. 
+When enabled, a reviewer only sees tasks that have been completed by all required annotators. 
+
+If your project is using auto distribution, then this means a reviewer only sees tasks that have met the **Annotations per task minimum** threshold. 
+
+If your project is using manual distribution, then this means a reviewer only sees tasks in which all assigned annotators have submitted an annotation. 
 
 Note that in most cases, skipped tasks do not contribute towards meeting the minimum.