Hey Bob.. yeah I posted this event in the Phantom facebook groups a couple of times last week..
I do not think the areas that I fly in has had much relevance over all.. I've flown over a mile from in front of my house many times as well as 2x at this field yesterday (comparison being that one has heavy WIFI/RF interference, and the other has near zero).. It just seems that my phantom has things inside working very well together (electrical tolerances or tuning), AND/OR I just do a good job with adjusting my antenna orientation as I'm flying.
I learned rather conclusively yesterday that the further I slide my phone away from the control antenna, I was able to go further (as opposed to centering the phone in the clamp, I slide it further and further to the left each time I got the lost control message.. and was able to regain control, and continue flying away)
I have seen other people post on here and on FB saying that they get similar distance results (again, with no modifications and no app)..