I cooked on my new 22.5 last Saturday and confirmed what I had read about the minor design flaw wherein the charcoal grate, sitting on the lower leg bolts inside the fire chamber, interferes slightly with the lower metal tangs that protrude from the vent diaphram into the four vent holes.
The degree of interferance is perhaps slight but when you want to close or open entirely it prevents you.
My fix was to fabricate three "angle" brackets 1 1/2" on the long side with a bolt hole at 3/4" and 1" on the other end and a bend of approx 60 degrees at the angle point. I used 3/16x1 bar to fabricate these.
I then simply removed the lower leg bolt nut and placed the brackets over the bolt and replaced the nut.
The photos show it pretty well. The solution was fast and effective.