Some of the links on this forum allow SMF, at no cost to you, to earn a small commission when you click through and make a purchase. Let me know if you have any questions about this.
What it will probably do is increase your fuel consumption. The PID controller will work to maintain your set temperature no matter how much food you have on there. But the more food you have on there, the more fuel it will take for the controller to maintain the temp you set. So your temp and cook time should be fine, but you may notice you're burning more fuel when you've got a full smoker.