the flight time from the battery is totally dependant on how the drone is being flown ,so if you use sport mode it will not fly as long as it would if you were in Cine mode ,like wise every time you climb you will be using more battery than you would in level flight ,also weather can have an effect on battery life as can the cold ,your post is the first i have heard of a power saving mode ,lipos once they are below around 40% charge ,will struggle with current flow when a large power demand is made of them, and this can trigger a low battery warning as the cells voltage drops significantly ,and will also cause the drone to self land,if one or more cells voltage drops into the 3 volt range