I have a Pace ADS200 soldering iron that I really like. When it came time to upgrade, I decided to switch from the "standard" tips to the "ultra" tips. My understanding that the ultras have greater thermal mass and might react a little better when you have to hit a ground pin that sinks more heat to the ground plane than your usual signal pads. However, as soon as I started using this tip, it didn't feel right. The solder didn't flow, didn't melt like it should.
Checking using my budget knock-off soldering iron tip tester, I found that at a setting of 370C, my standard tip measured out at 350C, whereas the ultra tip measured out at 330C. Now, I don't trust the absolute accuracy of the knock-off tip tester any more than I can throw it, but I do trust the relative difference in the readings. I repeated it multiple times to make sure it wasn't biased by me applying the tip to the tester incorrectly, and the results were repeatable. The ultra tip runs ~ 20C cooler.
Is this a known issue? I can just make a note of having to set the temperature 20C higher when I use the ultra tips.