The sides of the aperture tilt outwards slightly to compensate for keystoning from the projection booth being built higher than the screen center line. The curve in the lower part of the picture that seems to consume so much of the image is necessary because the screen had a moderate curvature. While the aperture dimensions look odd when seen against the full frame, they create a properly masked image on the theatre screen, utilizing as much of the original film as can be shown in this particular theatre. 70mm projector aperture plate cut for curved screen with high projector angle, defined by red boundary in the photo above. The Moral of the Story Put away your rulers and take the video magazines with a grain of salt.
Perfection exists nowhere.
If a film looks okay on your TV then don't worry about the aspect ratio. This ratio, and the image content, represents the most faithful reproduction of the film frame that is possible from a 35mm reduction element. Beeeutiful Image Careful inspection of the frame reveals that it takes in virtually all available image area. The new DVD frame is the maximum image available for a 35mm reduction print. The Patton DVD is one of the best transfers of a roadshow film that you're likely to see.