Map Pilot bug in creating survey area

If you create a survey grid with 4 outer points, and say it adds up to 10 acres. Now add a 5th point and increase the area to 15 acres.   If you remove that 5th point the total acreage size does NOT return to the 10 acres. It remains at the 15 acre size.

The battery and time to fly totals seem to change properly, but not the total acreate.