I'm seeing a spattering of Phantom 2 Vision/Vision+ shells available, now, that are being termed "new style". Anyone know if they're 100% compatible with older P2Vs (my P2V currently has the "old style" shell, apparently)? What is the larger access opening for, exactly (why was the design change needed)? And does the loss of that 5th center screw mean I won't be able to mount something, down the road, that I might want to mount? thanks!