Congrats on the seasoning run, Jerz! IMO, watching temps with an empty smoker is an exercise in frustration. Watching them with a meat load and water pan is a totally different thing. The unit is designed to cook meat, not maintain a constant temp when empty. The meat absorbs heat, as does the water pan. When the element cycles on and off, the internal cooker temp is maintained by all the stuff in there that has absorbed heat, thus smaller temp swings. In an empty smoker, nothing will hold heat once the element goes off.
I've never been really concerned with monitoring the smoker temp, as my cooks always turn out relatively close to plan. I finally bought a Maverick 732 and, just for fun, watched the cooker temp a couple of weeks ago while smoking a Boston butt...I was absolutely amazed that the largest swing I saw was about 10-degrees, and most of the time it was either dead-on, or within 5 degrees. I can certainly live with that! So, don't get to wrapped up on cooker temp and swings - just cook some Q and don't stress! This really is a smoker that you don't have to babysit!