I don't understand why people try to fly it so close to the end of the battery. Hell, I won't fly it over anything except a stable surface if the battery is under 50%. In my last video when I was filming surfers I did that at the start of the video. Once I hit about 50% - 55%, I brought it back to get some coast line shots to run the battery down lower.
In general, I won't run my batteries under 25% (Unless it's a VERY low ground hover, like a selfie). Every few runs with the batteries, I will run them to 16% by landing and just letting the blades spin. This was a value that was recommended on a few different posts about batteries.
I have seen it start to lose lifting power when the batteries get under 25%.
Be safe ... and if you want longer flight times, buy some extra batteries. Yep, they are expensive but way cheaper then replacing the whole **** drone.