Jeff,
If you only had 2 bricks in a 3D, that's probably not that bad. That's a lot of airspace to control with very little heat sink. I use these numbers in my 3D, based on an autotune I had done in a standard 3 with the standalone Auber PID:
P 62
I 900
D 112
They hold pretty tight, so I'm happy. The stock numbers worked for me, too, but these are just a little better (at least in mine). This is simply a programming issue, not any kind of failure of the controller. These boards are accurate, but if you try to hold temps within a degree or two in essentially an empty box (2 bricks vs. volume of space), it's very hard for the controller to adjust for that. However, even the variations you show are well-below the temperature swings of the analog controller, and BBQ isn't unforgiving. There's guys with stick burners that would kill for temps that close!

Not trying to make light of your disappointment, but this is a smoker, not a scientific test chamber.
One more thing - in the temp numbers you posted,
you can pretty much disregard the .3, .5 and .7 hour readings. This is the heat-up phase, and it will never be exact (the element has to heat, and then cool). This period also has absolutely NO effect on the outcome of your meat. Sometimes it takes around an hour, or so, to "settle in" and maintain the same temp. As you saw around the one hour point, it was pretty close. Had you let this program run longer, I have no doubt it would have stabilized very close to 135, which by the way, is a very low temp to smoke at, so this was truly a "stress test!"
When it switched to 155, you also did not give it time to get through the heating phase. Please remember that this is an electric element that doesn't heat & cool instantaneously. You only gave it 18 minutes to stabilize! Not enough.
If it were me, I would throw a big ol' pork butt in there, set the program to 225 until it hits 190 internal, and eat some BBQ! I think you are over-analyzing how rapidly the controller can work, and expecting more than any electric element can deliver. It is extremely more accurate than any stick burner, and other analog-controlled electrics. No offense, my friend, just my 2¢...
