Hello fellow Phantom Pilots - I have a Phantom 2V+, purchased in late October, and really am enjoying the aircraft, and the experience, with many successful flights. I have seen lots of posts on this and the DJI forum(s), where one poses a question that suggests that one has not "done their homework". In other words, read the manual, find instructional videos to watch, do all (not just some) of the firmware/software/app updates, go through the pre-flight checklist each and every time you fly, and have done all of that, so I am not that guy. The ONLY problem that I am having is with regard to altitude, as displayed on my iPhone. This problem is a bit random, in that on some days, the altitude appears to be accurate, and on other days, no matter how long I wait (after all other systems are "go", compass orientation, gps satellites, home lock") before takeoff, I am showing -200 ft altitude or more. I can hover nearby, my Phantom needs occasional help in maintaining altitude in that hover, but it never seems to correct itself. The biggest issue for me (I tested this today, flying in NAZA mode), was when I switched S1 to Failsafe, with the Phantom visually at about 50 ft. altitude, it climbed dramatically. This suggests to me that it was correcting for the -200 ft. to attempt to get to the RTH 66 ft. No telling how it might go about landing! Any suggestions, known issues, etc.? Thanks!