The girdle on both ends of this rock are the same height. Viewing from another angle, the girdles on each side of the rock are much higher than the girdle on either end. The bezel wire needs to be wider to accommodate the side girdle height, the higher of the two.
This stone will rock when pushing the bezel wire in, so e6000 can be your friend. In most cases, glue is not used when bezel setting cabochons, but stones are another matter. Leveling stones is not new. Stones, nuggets and thin cabochons in early turquoise jewelry were set with cushions of sawdust, and sometimes cardboard shims, under them. E6000 does not mold, cushions the stone, and fills the gaps around the stone as well as holding it in place. After the glue is set, pushing the bezel in is easy because the stone does not move.