Numbers mean nothing when your pins still aren't tight after five years of practice.

My old art teacher used to yell at me every single class about my death grip, said I was gonna snap a pencil in half one day. Took 15 years and a random youtube short for it to finally sink in. Now I catch myself holding it like a feather and my lines are still shaky, so I traded one problem for another. Sometimes I still grip it hard when I'm stressed and my hand cramps up like I just did 50 push ups. At least we're not alone in this, right?

Wait, thirty five degrees WORSE with a $240 tube? That just seems backwards to me. In my experience, those tubes usually even things out a little, or at least they're not supposed to make things that much worse. You're sure you didn't place it too close to the coals or maybe the vent is pulling air through it weird? I'd double check that you don't have it sitting in the path of the main draft, cause that could definitely mess with your readings. Take this with a grain of salt, but I've seen people move the tube to the opposite side and it fixed most of their swings overnight.