Welcome to the board semperrob!
You'll find a lot of folks experienced the same type of temperature differences you have. There are a couple of mods to help even things out. But don't feel like the CharGriller is the problem. Uneven temperatures are inherent to smaller smokers made from thinner metals and practically everyone with a back yard residential smoker deals with this issue. Extending the smoke stack to grate level, inverting the charcoal pan like a tuning plate, and adding a baffle to the firebox opening all do a small part in leveling out temperatures across the board. The Bandera like mine has dozens of mods available to help it along.