It only encodes orientations that result from rotation around the axis perpendicular to the line of sight (in other words, the rotations that can be reversed by display software). Parent was asking about the orientation with camera above the subject pointing directly down. I don't think EXIF can encode that -- there's no reason to, since display software has no way to reverse it.
I don't have iPhone, but almost every phone uses same orientation for photo as for GUI to avoid confusion. Orientation for GUI is usually changed with some hysteresis and other filtering, so probably answer is "The same orientation as it was before rotating in this position".
