This morning I did 43160 feet and back with my mavic. Certainly not a world-beating record but I learned some things about standard LiPO batteries with the mavic on this one. I know that everybody is on the high-voltage tip right now , but the standard LiPO batteries are amazing in the last 12%. I flew about 7000 feet in low-power mode at 22 miles per hour and I only used 6% battery. I'm figuring I have anywhere between 6 and 8 minutes left of flight time after I hit Landing mode with the 5200. I doubt very seriously the high-voltage battery would come close to that. I believe the saddlebag battery charges the main battery in landing mode. I don't know I just figured I'd share that with you guys. In my opinion though if the mavic was faster in landing mode the standard lipo would be superior to the high voltage batteries , but because it only does 22 or 23 miles an hour they can't make up the difference.
That's an excellent flight! Yes, the multistar lipo must be flown heavily on bottom end to extract the energy. The external battery should not charge the main battery during flight, but most current should be flowing from the external as you get lower in voltage. When you land it will charge the main. You'll I likely never get all the energy out without running main battery to 0. I bet if you check the external you still have more than 3.7v/cell, unless you have a very warm day which effectively reduces the internal resistance on the battery.
If my flight and Unknown Caller's are not considered, them this is the top flight on the leaderboard. Great job!