Just a thought for testing flight time of batteries. Hovering uses more energy than flying does. And most advertised flight times are from takeoff to critical battery auto landing.
If you really want to know how long your battery will last in an emergency, simply take off and hover in a safe area, about 2 meters up and let it hover until it autolands on critical battery. I haven't tried it with my
Mavic 3 but I did test my P3 batteries once using this method and all of then made it into the 21 minute mark. P3 batteries are rated for 23 min max.