Electric smokers, like an electric or gas oven (and your furnace for that matter) will fluctuate. If the controller is purely analog, you can set the temperature for 225 degrees. It will heat up to 225, and continue to a somewhat predetermined point maybe 240 on the high side, and the thermostat will cut the power. The temp will gradually drop to another somewhat pre-determined point well below the desired temperature, maybe 200 degrees, and then power will resume as will the heat. You can have a 15, 20, 25 degree difference high and low of your set point.
On a digitally controlled smoker, the temperature fluctuations or swing high and low of the set temp are very minor, or should be if designed properly. My CS is digital and holds steady within a degree or two. I can hear it it click on/off throughout a smoke. My Smokin-it has a built in PID. It is silent, and I have yet to see it vary by more than a single degree.
Your oven and HVAC work the same way. They cycle on and off to maintain a fairly accurate temperature of your choosing. It all depends upon the quality of the components and quality control during manufacture. And even the best will, over time, begin to wear out.
One other area is the smoker cabinet itself. If it is poorly insulated it will lose heat rapidly and your smoker will cycle more often, and may even struggle to to get to the temperature you select depending upon weather conditions.
One other item of note: Make sure your Maverick is calibrated. Check it against the temperature of boiling water for your location (altitude above sea level changes temperatures) as well as it's reading of ice water.
