I'm smoking ribs as we speak. Using wsm 22" had it about a year or so and have never used the bottom grate. I've got a slab on both lower and upper. I'm using maverick ready check dual therm's on both upper and lower. The temp is about 25 degrees lower on the bottom grate. Is that normal? I'm keeping the upper temp between 225 and 230. I guess this means when I go to rapp I will have to keep the lower ones a bit longer. Help. Thanks Gary