Actually, no, I've never seen that before. Only flat. If the tension is correct the belt will "want" to stay centered on the pulley.
Question for you guys with VCT zetecs: Did you have to loosen the cam pulley bolts to get rid of the tension in between the pulleys? Last time I did it, I didnt loosen them, but instead marked a tooth on each pulley, and the corresponding tooth on the old belt. I then counted the number of teeth in between, and duplicated the marks in the proper place on the new belt. I took the flat metal tool out, put the belt over the cam pulleys with the marks matching, and then replaced the flat metal piece to hold the tension. At that point, I spun the crank counter clockwise a bit, set the belt with the marks matching, and then rotated it clockwise to take up the slack on the right side. I tensioned it up and all was well.
Now, some have said that it's easier just to keep the flat bar in the cam ends, put the belt all around, and then with tension on the belt, tighten those cam pulley bolts. This to me seemed like far more work, but this is the "right" way to do it.
Anyone have thoughts on my way vs. the real way? I understand that if the belt was already broken and out of time, my way wouldn't work at all. But for routine replacement, I would think it's far easier.