Don't panic...perfectly normal to see big temp swings with an empty smoker! When there's nothing in there to absorb and retain the heat, the element kicks on and off a lot more. I usually recommend leaving the temp probe out during seasoning. When you have a meat load, and water pan, inside, it retains heat that's generated in the smoke box, and the temp swings get considerably less. In my #1, I only see +/- 10-degree swings, and usually holds pretty close to the set temp. When the smoker is empty, there's nothing but reflective, hard, stainless steel. It doesn't really "absorb" the heat very well, so you see huge temp swings. Also, I would guess your temp probe was low, close to the smoke box? That might explain the high temps you saw.
Check it on your first smoke, with meat and a water pan, and I bet you'll see a big difference.