I find those weight ratings in general misleading, because the camera is not just dead weight in a testing lab. Yes, a tripod rated for 22 lbs. won't collapse with a 22 lb. camera on it, but will the camera really be steady when you have a long lens and the bellows racked out all the way and the wind blowing, or when you have a 35mm camera with a 600mm lens and an extension tube to photograph a sparrow 10 feet away with Kodachrome 64? The forces being applied to the head may be greater than the rating under those circumstances.
The photographer I mentioned above who uses a Tiltall for his 8x10" generally shoots interiors, so no wind problems, and he uses short lenses. A Tiltall is probably enough for that, but I wouldn't use it for landscapes with the 8x10".