I'm sure you are correct on the offset affecting both the upper and lower end.
If someone wants to use the offset for the Vigil, they should know the actual window(s):
3.3.1. “PRO” Mode
The Vigil® cutter activates at 840 ft. (256 meters) and below until 150 ft. (46 meters),
if the freefall speed is equal or superior to 35 m/sec. (78 mph or 126 km/h)*
3.3.2. “STUDENT” Mode
The Vigil® cutter activates at 1040 ft. (317 meters) and below until 150 ft. (46 meters),
if the freefall speed is equal or superior to 20 m/sec. (45 mph or 72 km/h)*
3.3.3. “TANDEM” Mode
The Vigil® cutter activates at 2040 ft. (622 meters) and below until 150 ft. (46 meters),
if the freefall speed is equal or superior to 35 m/sec. (78 mph or 126 km/h)*