I'm not sure why I'm the first to say this, but adjust your intake. It doesn't take much, close it just slightly. You have to understand the PBC is designed to run between about 260-330. That's a fairly big range if you are picky about temps (I am so I'm with you there). Using the settings of 1/4 open or 1/2 open depending on elevation will not help you get a particular temp, but it will get you close. I used that as a baseline. Plus your idea of 1/4 open and mine are gonna be different, thus different cook temps, right? You will have to tweak it until you get what you like. The lowest temp I cook at (and mostly use) is 275°. I set mine up to run at that temp. When I wanna go higher it's easy to crack the lid. Figure out which temp you will use most and setup the intake for that temp. Just loosen your intake screw slightly and make the adjustments you need. Once you are happy with the cook, tighten the screw and you are good.
Unless you use the lighter fluid lighting method, another thing you can do as well to tweak temps, and in your case lower temps, is to use a couple less lit coals to start (most people use 40). I've been laughed at (by folks without a PBC) by stating this before but it works, trust me.. I typically use 36.....if you use lighter fluid obviously you aren't counting coals so this wouldn't apply.
Also, if you use the lighter fluid method you will initially get much higher temps that will settle down. If you light coal in a chinmey it'll come right up to temp pretty much right away. It may overshoot for 5-10 minutes but you should wait about 15 min after dumping the lit coals to put your meat in anyway. And it won't go over by much. Maybe 15-25°. But it's settles down really quick.
Good luck!
