Well I hope you were wearing a ski mask when you bought that stove cause you stole it!
Yes you should never have burning coal dumping off of the grate. Whether or not you are adjusted properly for current conditions is another matter. I assume you have a thermostat installed off of the controller? If you are meeting your setting, great. You may not need to be pushing as much coal as you are currently. My boiler uses the exact stoker your stove does. Right now, I only have about 2"-3" of burning coal on my grate and several inches of ash at the end. You might try backing it down some. It's a balancing act. You don't want to burn more than you need to obviously. Remember that as you make changes in any settings, be patient as it takes some time to show up in your results unlike wood.
Your maintenance settings may also need to be tweeked. Time on and time between cycles. Lots to read here on the forum about your stove. Drink it up.