diff --git a/changelog.md b/changelog.md
index 04a2c94a..4c8fbf3e 100644
--- a/changelog.md
+++ b/changelog.md
@@ -25,6 +25,7 @@ Saves from 8.x are not compatible with 9.0.0.
 * **[UI]** Fixed deleting waypoints in custom flight plans deleting the wrong waypoint.
 * **[UI]** Fixed flight properties UI to support F-15E S4+ laser codes.
 * **[UI]** In unit transfer dialog, only list control points that are reachable from the control point units are being transferred from.
+* **[UI]** Fixed UI bug where altering an "ahead of package" TOT offset would change the offset back to a "behind pacakge" offset.
 
 # 8.1.0
 
diff --git a/qt_ui/windows/mission/flight/settings/FlightPlanPropertiesGroup.py b/qt_ui/windows/mission/flight/settings/FlightPlanPropertiesGroup.py
index 720d5eda..96b63a36 100644
--- a/qt_ui/windows/mission/flight/settings/FlightPlanPropertiesGroup.py
+++ b/qt_ui/windows/mission/flight/settings/FlightPlanPropertiesGroup.py
@@ -51,10 +51,10 @@ class FlightPlanPropertiesGroup(QGroupBox):
 
         tot_offset_layout.addWidget(QLabel("TOT Offset (minutes:seconds)"))
         tot_offset_layout.addStretch()
-        negative_offset_checkbox = QCheckBox("Ahead of package")
-        negative_offset_checkbox.setChecked(negative)
-        negative_offset_checkbox.toggled.connect(self.toggle_negative_offset)
-        tot_offset_layout.addWidget(negative_offset_checkbox)
+        self.negative_offset_checkbox = QCheckBox("Ahead of package")
+        self.negative_offset_checkbox.setChecked(negative)
+        self.negative_offset_checkbox.toggled.connect(self.toggle_negative_offset)
+        tot_offset_layout.addWidget(self.negative_offset_checkbox)
 
         self.tot_offset_spinner = QTimeEdit(QTime(hours, minutes, seconds))
         self.tot_offset_spinner.setMaximumTime(QTime(59, 0))
@@ -113,9 +113,12 @@ class FlightPlanPropertiesGroup(QGroupBox):
             )
 
     def set_tot_offset(self, offset: QTime) -> None:
-        self.flight.flight_plan.tot_offset = timedelta(
+        offset = timedelta(
             hours=offset.hour(), minutes=offset.minute(), seconds=offset.second()
         )
+        if self.negative_offset_checkbox.isChecked():
+            offset = -offset
+        self.flight.flight_plan.tot_offset = offset
         self.update_departure_time()
 
     def toggle_negative_offset(self) -> None: