This sounds like an incorrect assembly problem - either one of the elements "reversed" or incorrect element spacing. Is this a change in lens performance, i.e., after lens or shutter repair or maintenance, or has it been like this since new?

Is there any evidence of clouding or fungus, or cement separation?

When you say that the area affected is "off center and elliptical when movements are used", what movements are in question ... "tilts" and "swings", where the film plane is no longer parallel to the center of the optical axis, or do parallel movements - "rises" and "falls" - alone cause this effect (which would really baffle the hell out of me)?

*Some* fall-off (the extremes of the field receive less light than the center) is to be expected, but the "out-of-focusness" in the center - CAN the center area be focused? - seems to be out of the ordinary.